diff --git a/vscode/src/panel/handlers/issues.ts b/vscode/src/panel/handlers/issues.ts
index f7f6fb4..baa4940 100644
--- a/vscode/src/panel/handlers/issues.ts
+++ b/vscode/src/panel/handlers/issues.ts
@@ -21,6 +21,7 @@ import {
   closeIssue,
   deleteBranch,
   deleteIssue,
+  getDependencies,
   getPullRequest,
   GiteaApiError,
   mergePullRequest,
@@ -35,6 +36,7 @@ import { pickRandomIssueColor, themeColorIdToIconUri } from '../issueColor'
 import { makeNonce } from '../KanbanPanel'
 import { cleanupFeatureBranch } from './branchCleanup'
 import * as sessions from './sessions'
+import { canResetToTodo, todoResetStateExtra, todoResetUiPatch } from './todoReset'
 
 export async function handleColumnChange(panel: KanbanWebviewPanel, issueNumber: number, toColumn: IssueColumn): Promise<void> {
   if (toColumn === 'in-progress') {
@@ -42,6 +44,11 @@ export async function handleColumnChange(panel: KanbanWebviewPanel, issueNumber:
     return
   }
 
+  if (toColumn === 'todo') {
+    await handleResetToTodo(panel, issueNumber)
+    return
+  }
+
   if (toColumn !== 'done') {
     logger.add({
       level: 'info',
@@ -554,6 +561,290 @@ export async function handleColumnChange(panel: KanbanWebviewPanel, issueNumber:
   })
 }
 
+export async function handleResetToTodo(panel: KanbanWebviewPanel, issueNumber: number): Promise<void> {
+  const rollback = (fromColumn: IssueColumn | undefined): void => {
+    panel.postMessage({
+      type: 'issue/patch',
+      issueNumber,
+      patch: { column: fromColumn ?? 'in-progress' },
+    })
+  }
+
+  const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
+  if (!workspaceRoot) {
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: '请先打开一个工作区文件夹',
+      dismissOnTimer: 5000,
+    })
+    rollback(undefined)
+    return
+  }
+
+  const remote = await detectRepo(workspaceRoot)
+  if (!remote) {
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: '当前工作区没有 Gitea 远程仓库',
+      dismissOnTimer: 5000,
+    })
+    rollback(undefined)
+    return
+  }
+
+  const token = await getToken(panel.context, remote.host)
+  if (!token) {
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: '请先完成 Gitea 配置',
+      dismissOnTimer: 5000,
+    })
+    rollback(undefined)
+    return
+  }
+
+  // ① 读 state → 守卫（todo no-op / done 拒绝）→ 确认；取消 rollback 必须先有 fromColumn
+  let prStr: string | undefined
+  let worktreePath: string | undefined
+  let fromColumn: IssueColumn | undefined
+  let featureBranchFromState: string | undefined
+  try {
+    const stateObj = await panel.readIssueState(issueNumber)
+    if (typeof stateObj.pr === 'string' && stateObj.pr.length > 0)
+      prStr = stateObj.pr
+    if (typeof stateObj.worktreePath === 'string' && stateObj.worktreePath.length > 0)
+      worktreePath = stateObj.worktreePath
+    if (
+      typeof stateObj.column === 'string'
+      && ['todo', 'in-progress', 'review', 'done'].includes(stateObj.column)
+    ) {
+      fromColumn = stateObj.column as IssueColumn
+    }
+    if (typeof stateObj.branch === 'string' && stateObj.branch.length > 0)
+      featureBranchFromState = stateObj.branch
+  }
+  catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    logger.add({
+      level: 'error',
+      source: 'panel',
+      message: `读取工单 #${issueNumber} 状态失败`,
+      details: message,
+    })
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: `读取工单 #${issueNumber} 状态失败: ${message}`,
+      dismissOnTimer: 6000,
+    })
+    rollback(undefined)
+    return
+  }
+
+  if (fromColumn === 'todo')
+    return
+
+  if (!canResetToTodo(fromColumn ?? 'in-progress')) {
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: `已完成的工单 #${issueNumber} 不能重置为待办`,
+      dismissOnTimer: 5000,
+    })
+    rollback(fromColumn)
+    return
+  }
+
+  const choice = await window.showWarningMessage(
+    `确定将工单 #${issueNumber} 重置为待办？将停止会话、删除 worktree / 未合并 PR / feature 分支，实施进度不可恢复。`,
+    { modal: true },
+    '重置为待办',
+  )
+  if (choice !== '重置为待办') {
+    rollback(fromColumn)
+    return
+  }
+
+  // ② 停会话 → 删 worktree（失败即停）→ 未合并 PR 关掉 → 清 feature 分支
+  for (const [terminal, origin] of panel.terminalOrigin) {
+    if (origin.issueNumber === issueNumber) {
+      try {
+        terminal.dispose()
+      }
+      catch {
+        // dispose 失败也无所谓，VS Code 自己会清掉关闭事件
+      }
+    }
+  }
+
+  if (worktreePath) {
+    const abs = resolveWorktreePath(worktreePath, workspaceRoot)
+    if (fs.existsSync(abs)) {
+      const settingsForHook = getSettings(panel.context)
+      await panel.dispatchWorktreeHook('pre-remove', {
+        workspaceRoot,
+        worktreePath: abs,
+        branch: resolveFeatureBranch({ stateBranch: featureBranchFromState }),
+        issueNumber,
+        mainBranch: settingsForHook.devBranch || 'main',
+        customScriptPath: settingsForHook.worktreePreRemoveScript,
+      })
+      const killed = killProcessesUsingWorktree(abs)
+      if (killed.length > 0) {
+        const list = killed
+          .map(h => `  pid ${h.pid}: ${h.cmd.length > 80 ? `${h.cmd.slice(0, 80)}…` : h.cmd}`)
+          .join('\n')
+        logger.add({
+          level: 'warn',
+          source: 'panel',
+          message: `重置待办前已杀掉占用进程 (issue #${issueNumber})`,
+          details: list,
+        })
+      }
+      try {
+        await removeWorktreeDir(workspaceRoot, abs)
+        logger.add({
+          level: 'info',
+          source: 'panel',
+          message: `已清理 worktree ${worktreePath} (issue #${issueNumber})`,
+        })
+      }
+      catch (err) {
+        const message = err instanceof Error ? err.message : String(err)
+        logger.add({
+          level: 'error',
+          source: 'panel',
+          message: `清理 worktree 失败 (issue #${issueNumber})`,
+          details: message,
+        })
+        panel.postMessage({
+          type: 'toast/show',
+          id: makeNonce(),
+          level: 'error',
+          message: `删除 worktree 失败 #${issueNumber}: ${message}`,
+          dismissOnTimer: 6000,
+        })
+        rollback(fromColumn)
+        return
+      }
+    }
+  }
+
+  let prHeadRef: string | undefined
+  if (prStr) {
+    const prIndex = Number.parseInt(prStr, 10)
+    if (!Number.isFinite(prIndex)) {
+      panel.postMessage({
+        type: 'toast/show',
+        id: makeNonce(),
+        level: 'error',
+        message: `工单 #${issueNumber} 的 PR 字段无效: ${prStr}`,
+        dismissOnTimer: 6000,
+      })
+      rollback(fromColumn)
+      return
+    }
+    try {
+      const pullRequest = await getPullRequest({
+        host: remote.host,
+        token,
+        owner: remote.owner,
+        repo: remote.repo,
+        index: prIndex,
+      })
+      prHeadRef = pullRequest.headRef
+      if (!pullRequest.merged) {
+        await closeIssue({
+          host: remote.host,
+          token,
+          owner: remote.owner,
+          repo: remote.repo,
+          issueNumber: prIndex,
+        })
+      }
+    }
+    catch (err) {
+      const message = err instanceof Error ? err.message : String(err)
+      logger.add({
+        level: 'error',
+        source: 'panel',
+        message: `处理 PR #${prIndex} 失败 (issue #${issueNumber})`,
+        details: message,
+      })
+      panel.postMessage({
+        type: 'toast/show',
+        id: makeNonce(),
+        level: 'error',
+        message: `处理 PR #${prIndex} 失败 (issue #${issueNumber}): ${message}`,
+        dismissOnTimer: 6000,
+      })
+      rollback(fromColumn)
+      return
+    }
+  }
+
+  const featureBranch = resolveFeatureBranch({
+    stateBranch: featureBranchFromState,
+    prHeadRef,
+  })
+  if (featureBranch) {
+    const settingsForBranchCleanup = getSettings(panel.context)
+    await cleanupFeatureBranch({
+      workspaceRoot,
+      branch: featureBranch,
+      issueNumber,
+      devBranch: settingsForBranchCleanup.devBranch,
+      autoBuildBranch: settingsForBranchCleanup.autoBuildBranch,
+      remote,
+      token,
+    })
+  }
+
+  // ③ 落盘清空实施痕迹 → UI patch 用 null（postMessage 会丢 undefined）
+  try {
+    await panel.mergeIssueState(issueNumber, todoResetStateExtra())
+  }
+  catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    logger.add({
+      level: 'error',
+      source: 'panel',
+      message: `持久化 column=todo 失败 (issue #${issueNumber})`,
+      details: message,
+    })
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: `保存工单 #${issueNumber} 状态失败: ${message}`,
+      dismissOnTimer: 6000,
+    })
+    rollback(fromColumn)
+    return
+  }
+
+  panel.postMessage({
+    type: 'issue/patch',
+    issueNumber,
+    patch: todoResetUiPatch(),
+  })
+  panel.postMessage({
+    type: 'toast/show',
+    id: makeNonce(),
+    level: 'success',
+    message: `工单 #${issueNumber} 已重置为待办`,
+    dismissOnTimer: 5000,
+  })
+}
+
 /**
  * Handle a "drag to in-progress" kanban move.
  *
@@ -1401,14 +1692,36 @@ export async function handleSetDependency(panel: KanbanWebviewPanel, issueNumber
   }
 
   try {
-    await addDependency({
+    // Gitea 允许多依赖，loader 只取第一个；拖到另一张卡片换父时必须先清掉旧前置。
+    const deps = await getDependencies({
       host: remote.host,
       token,
       owner: remote.owner,
       repo: remote.repo,
       index: issueNumber,
-      dependencyIndex: prerequisiteNumber,
     })
+    for (const dep of deps) {
+      if (dep.number !== prerequisiteNumber) {
+        await removeDependency({
+          host: remote.host,
+          token,
+          owner: remote.owner,
+          repo: remote.repo,
+          index: issueNumber,
+          dependencyIndex: dep.number,
+        })
+      }
+    }
+    if (!deps.some(d => d.number === prerequisiteNumber)) {
+      await addDependency({
+        host: remote.host,
+        token,
+        owner: remote.owner,
+        repo: remote.repo,
+        index: issueNumber,
+        dependencyIndex: prerequisiteNumber,
+      })
+    }
   }
   catch (err) {
     const message = err instanceof Error ? err.message : String(err)
diff --git a/vscode/src/panel/handlers/todoReset.test.ts b/vscode/src/panel/handlers/todoReset.test.ts
new file mode 100644
index 0000000..731f80e
--- /dev/null
+++ b/vscode/src/panel/handlers/todoReset.test.ts
@@ -0,0 +1,62 @@
+import { describe, expect, it } from 'vitest'
+import { canResetToTodo, todoResetStateExtra, todoResetUiPatch } from './todoReset'
+
+describe('canResetToTodo', () => {
+  it('允许从 in-progress 重置', () => {
+    expect(canResetToTodo('in-progress')).toBe(true)
+  })
+
+  it('允许从 review 重置', () => {
+    expect(canResetToTodo('review')).toBe(true)
+  })
+
+  it('已在 todo 不允许（handler 走 no-op）', () => {
+    expect(canResetToTodo('todo')).toBe(false)
+  })
+
+  it('done 不允许（handler 拒绝并 rollback）', () => {
+    expect(canResetToTodo('done')).toBe(false)
+  })
+})
+
+describe('todoResetStateExtra', () => {
+  it('清空实施痕迹并回到 todo，保留规划侧字段不在 extra 里', () => {
+    const extra = todoResetStateExtra()
+    expect(extra).toEqual({
+      column: 'todo',
+      branch: '',
+      implementStatus: '',
+      pr: '',
+      prMerged: false,
+      prMergedAt: '',
+      worktreePath: '',
+      implementSessionId: '',
+      reviewSessionId: '',
+    })
+    expect(extra).not.toHaveProperty('sessionId')
+    expect(extra).not.toHaveProperty('planFile')
+    expect(extra).not.toHaveProperty('specFile')
+    expect(extra).not.toHaveProperty('profilePath')
+    expect(extra).not.toHaveProperty('brainstormProfilePath')
+    expect(extra).not.toHaveProperty('testProfilePath')
+    expect(extra).not.toHaveProperty('color')
+    expect(extra).not.toHaveProperty('autoReview')
+  })
+})
+
+describe('todoResetUiPatch', () => {
+  it('用 null 清空 UI 字段，避免 postMessage 丢掉 undefined', () => {
+    expect(todoResetUiPatch()).toEqual({
+      column: 'todo',
+      branch: null,
+      implementStatus: null,
+      pr: null,
+      prMerged: false,
+      prMergedAt: null,
+      worktreePath: null,
+      implementSessionId: null,
+      reviewSessionId: null,
+      worktreeExists: false,
+    })
+  })
+})
diff --git a/vscode/src/panel/handlers/todoReset.ts b/vscode/src/panel/handlers/todoReset.ts
new file mode 100644
index 0000000..cb33beb
--- /dev/null
+++ b/vscode/src/panel/handlers/todoReset.ts
@@ -0,0 +1,45 @@
+import type { IssueColumn } from '../../gitea/types'
+
+export function canResetToTodo(fromColumn: IssueColumn | undefined): boolean {
+  return fromColumn === 'in-progress' || fromColumn === 'review'
+}
+
+export function todoResetStateExtra(): Record<string, unknown> {
+  return {
+    column: 'todo',
+    branch: '',
+    implementStatus: '',
+    pr: '',
+    prMerged: false,
+    prMergedAt: '',
+    worktreePath: '',
+    implementSessionId: '',
+    reviewSessionId: '',
+  }
+}
+
+export function todoResetUiPatch(): {
+  column: 'todo'
+  branch: null
+  implementStatus: null
+  pr: null
+  prMerged: false
+  prMergedAt: null
+  worktreePath: null
+  implementSessionId: null
+  reviewSessionId: null
+  worktreeExists: false
+} {
+  return {
+    column: 'todo',
+    branch: null,
+    implementStatus: null,
+    pr: null,
+    prMerged: false,
+    prMergedAt: null,
+    worktreePath: null,
+    implementSessionId: null,
+    reviewSessionId: null,
+    worktreeExists: false,
+  }
+}
diff --git a/vscode/src/panel/messages.ts b/vscode/src/panel/messages.ts
index 4dbc360..8c402f2 100644
--- a/vscode/src/panel/messages.ts
+++ b/vscode/src/panel/messages.ts
@@ -42,7 +42,7 @@ export type ExtensionToWebview
   = | { type: 'issues/loading' }
     | { type: 'issues/update', issues: Issue[], scope: 'mine' | 'all', globalAutoReview: boolean, youtrackConfigured: boolean }
     | { type: 'issues/error', message: string }
-    | { type: 'issue/patch', issueNumber: number, patch: { autoReview?: boolean, specFile?: string, planFile?: string, prDiffFile?: string, sessionId?: string, implementSessionId?: string, reviewSessionId?: string, reviewSessionFileExists?: boolean, testSessionId?: string, pr?: string | null, implementStatus?: 'running' | 'done' | 'failed', column?: IssueColumn, worktreePath?: string | null, prMerged?: boolean, prMergedAt?: string, branch?: string | null, color?: string, worktreeExists?: boolean, brainstormTabOpen?: boolean, implementTabOpen?: boolean, reviewTabOpen?: boolean, testTabOpen?: boolean, profilePath?: string, brainstormProfilePath?: string, testProfilePath?: string } }
+    | { type: 'issue/patch', issueNumber: number, patch: { autoReview?: boolean, specFile?: string, planFile?: string, prDiffFile?: string, sessionId?: string, implementSessionId?: string | null, reviewSessionId?: string | null, reviewSessionFileExists?: boolean, testSessionId?: string, pr?: string | null, implementStatus?: 'running' | 'done' | 'failed' | null, column?: IssueColumn, worktreePath?: string | null, prMerged?: boolean, prMergedAt?: string | null, branch?: string | null, color?: string, worktreeExists?: boolean, brainstormTabOpen?: boolean, implementTabOpen?: boolean, reviewTabOpen?: boolean, testTabOpen?: boolean, profilePath?: string, brainstormProfilePath?: string, testProfilePath?: string } }
     | { type: 'issue/pr-diff-summary-done', issueNumber: number }
     | { type: 'issue/append', issue: Issue, select?: boolean }
     | { type: 'issue/select-by-number', issueNumber: number }
diff --git a/vscode/webview-ui/src/App.tsx b/vscode/webview-ui/src/App.tsx
index 7286313..7bdbc15 100644
--- a/vscode/webview-ui/src/App.tsx
+++ b/vscode/webview-ui/src/App.tsx
@@ -366,6 +366,7 @@ export function App() {
                 onMergeBranch={mergeBranch}
                 onDeleteIssue={deleteIssue}
                 onCloseIssue={closeIssue}
+                onResetToTodo={n => changeColumn(n, 'todo', selectedIssue?.source, selectedIssue?.externalId)}
                 onCloseSessionTab={closeSessionTab}
                 onStartBrainstormSession={startBrainstormSession}
                 onUpdateAutoReview={updateIssueAutoReview}
diff --git a/vscode/webview-ui/src/components/BottomTabs.tsx b/vscode/webview-ui/src/components/BottomTabs.tsx
index f7c7648..7b93d31 100644
--- a/vscode/webview-ui/src/components/BottomTabs.tsx
+++ b/vscode/webview-ui/src/components/BottomTabs.tsx
@@ -42,6 +42,7 @@ interface BottomTabsProps {
   onMergeBranch: (issueNumber: number, branch: string) => void
   onDeleteIssue?: (issueNumber: number) => void
   onCloseIssue: (issueNumber: number) => void
+  onResetToTodo: (issueNumber: number) => void
   onCloseSessionTab: (issueNumber: number, kind: 'brainstorm' | 'implement' | 'review' | 'test') => void
   onStartBrainstormSession: (issueNumber: number) => void
   onUpdateAutoReview: (issueNumber: number, value: boolean) => void
@@ -128,6 +129,7 @@ export function BottomTabs(props: BottomTabsProps) {
             onMergeBranch={props.onMergeBranch}
             onDeleteIssue={props.onDeleteIssue}
             onCloseIssue={props.onCloseIssue}
+            onResetToTodo={props.onResetToTodo}
             onCloseSessionTab={props.onCloseSessionTab}
             onStartBrainstormSession={props.onStartBrainstormSession}
             onUpdateAutoReview={props.onUpdateAutoReview}
diff --git a/vscode/webview-ui/src/components/IssueDetailPanel.tsx b/vscode/webview-ui/src/components/IssueDetailPanel.tsx
index 906433f..512d58a 100644
--- a/vscode/webview-ui/src/components/IssueDetailPanel.tsx
+++ b/vscode/webview-ui/src/components/IssueDetailPanel.tsx
@@ -1,6 +1,6 @@
 import type { ReactNode } from 'react'
 import { useMemo, useRef } from 'react'
-import { CircleSlash, ExternalLink, GitMerge, Play, Terminal, Trash2, X } from 'lucide-react'
+import { CircleSlash, ExternalLink, GitMerge, Play, RotateCcw, Terminal, Trash2, X } from 'lucide-react'
 import type { ClaudeProfile } from '../hooks/useIssues'
 import type { Issue, IssueColumn } from '../types'
 import { COLUMN_LABELS, COLUMN_ORDER } from '../types'
@@ -68,6 +68,8 @@ interface IssueDetailPanelProps {
   onDeleteIssue?: (issueNumber: number) => void
   /** 关闭 Gitea 工单，不清理本地会话、worktree、PR 或分支。 */
   onCloseIssue: (issueNumber: number) => void
+  /** 将实施中 / 审查中的工单重置回待办（清 worktree / 未合并 PR / feature 分支）。 */
+  onResetToTodo: (issueNumber: number) => void
   /** Close the matching session terminal tab. The extension watches
    * onDidCloseTerminal and clears the corresponding `*TabOpen` flag, which
    * makes the X button vanish on its own. */
@@ -117,6 +119,7 @@ export function IssueDetailPanel({
   onMergeBranch,
   onDeleteIssue,
   onCloseIssue,
+  onResetToTodo,
   onCloseSessionTab,
   onStartBrainstormSession,
   onUpdateAutoReview,
@@ -572,6 +575,17 @@ export function IssueDetailPanel({
             avoid acting on a gitea issue of the same number. */}
         {issue.source !== 'youtrack' && (
           <>
+            {(issue.column === 'in-progress' || issue.column === 'review') && (
+              <button
+                type="button"
+                onClick={() => onResetToTodo(issue.number)}
+                title="重置为待办"
+                aria-label="重置为待办"
+                className="inline-flex shrink-0 items-center justify-center rounded border border-[var(--vscode-panel-border)] p-1 text-xs text-[var(--vscode-foreground)] hover:border-yellow-500/60 hover:bg-yellow-500/10 hover:text-yellow-500"
+              >
+                <RotateCcw className="size-3.5" />
+              </button>
+            )}
             <button
               type="button"
               onClick={() => onCloseIssue(issue.number)}
diff --git a/vscode/webview-ui/src/components/KanbanBoard.tsx b/vscode/webview-ui/src/components/KanbanBoard.tsx
index 7f5d6cc..f9eb324 100644
--- a/vscode/webview-ui/src/components/KanbanBoard.tsx
+++ b/vscode/webview-ui/src/components/KanbanBoard.tsx
@@ -1,25 +1,28 @@
-import { useEffect, useMemo, useRef, useState } from 'react'
+import type { CollisionDetection, DragEndEvent, DragStartEvent } from '@dnd-kit/core'
+import type { Issue, IssueColumn } from '../types'
 import {
+  closestCenter,
   DndContext,
   DragOverlay,
   KeyboardSensor,
   PointerSensor,
+  pointerWithin,
   useSensor,
   useSensors,
 } from '@dnd-kit/core'
-import type { DragEndEvent, DragStartEvent } from '@dnd-kit/core'
 import {
-  SortableContext,
   arrayMove,
+  SortableContext,
   sortableKeyboardCoordinates,
   verticalListSortingStrategy,
 } from '@dnd-kit/sortable'
-import { IssueCard } from './IssueCard'
-import { KanbanColumn } from './KanbanColumn'
+import { useEffect, useMemo, useRef, useState } from 'react'
 import { isIssueLocked } from '../lib/dependencies'
 import { compareIssuesInColumn } from '../lib/issueSort'
-import type { Issue, IssueColumn } from '../types'
+import { isColumnId, resolveKanbanDrag } from '../lib/kanbanDrag'
 import { COLUMN_ORDER } from '../types'
+import { IssueCard } from './IssueCard'
+import { KanbanColumn } from './KanbanColumn'
 
 interface KanbanBoardProps {
   issues: Issue[]
@@ -28,27 +31,18 @@ interface KanbanBoardProps {
   onCreateIssue?: () => void
   selectedId?: string | null
   onSelectIssue?: (id: string | null) => void
-  /**
-   * Called when a card moves to a new column via drag-and-drop, in addition
-   * to the optimistic `onIssuesChange`. Currently only invoked for moves
-   * targeting `done`; other column changes remain client-visual-only.
-   */
   onColumnChange?: (issueNumber: number, toColumn: IssueColumn, source?: 'gitea' | 'youtrack', externalId?: string) => void
-  /**
-   * Called when a drag gesture establishes a new prerequisite relationship
-   * (drop onto another todo card's middle 1/3) or moves to a sibling whose
-   * parent differs from the active card's current parent.
-   */
   onDependencySet?: (issueNumber: number, prerequisiteNumber: number) => void
-  /**
-   * Called when a drag gesture clears an existing prerequisite (e.g. drop
-   * onto the todo column's empty area, or onto a sibling at root level).
-   */
   onDependencyClear?: (issueNumber: number, prerequisiteNumber: number) => void
 }
 
-function isColumnId(id: string): id is IssueColumn {
-  return (COLUMN_ORDER as string[]).includes(id)
+const kanbanCollisionDetection: CollisionDetection = (args) => {
+  const pointerHits = pointerWithin(args)
+  if (pointerHits.length > 0) {
+    const cardHits = pointerHits.filter(c => !isColumnId(String(c.id)))
+    return cardHits.length > 0 ? cardHits : pointerHits
+  }
+  return closestCenter(args)
 }
 
 /**
@@ -152,174 +146,73 @@ export function KanbanBoard({
     setActiveId(String(event.active.id))
   }
 
-  /**
-   * Classify the drop position relative to the `over` card. Middle 1/3
-   * means nest (set prerequisite); the upper/lower 2/3 means sibling reorder.
-   * The 1/3-2/3 split is intentionally wider than 1/4-1/2-1/4 because the
-   * sortable strategy reflows during drag, so the user needs more room.
-   */
-  function detectDropZone(event: DragEndEvent): 'middle' | 'edge' {
-    const activeRect = event.active.rect.current.translated
-    const overRect = event.over?.rect
-    if (!activeRect || !overRect)
-      return 'edge'
-    const activeCenterY = (activeRect.top + activeRect.bottom) / 2
-    const overHeight = overRect.height
-    // Widen the nest zone to the middle 60% of the over card so user doesn't
-    // need pixel-precision. Edge zone is just the top/bottom 20% slivers,
-    // which are still enough for sibling-reorder gestures.
-    const middleStart = overRect.top + overHeight * 0.2
-    const middleEnd = overRect.top + overHeight * 0.8
-    return activeCenterY >= middleStart && activeCenterY <= middleEnd ? 'middle' : 'edge'
-  }
-
-  /**
-   * Walks up the prerequisite chain from `target`, returning true if
-   * `maybeAncestor` appears anywhere on the way. Uses a visited set so a
-   * pre-existing cycle in the data doesn't spin forever.
-   */
-  function isDescendant(maybeAncestor: number, target: number, all: Issue[]): boolean {
-    const visited = new Set<number>()
-    let current: Issue | undefined = all.find(i => i.number === target)
-    while (current && current.prerequisite != null) {
-      if (visited.has(current.number))
-        return false
-      visited.add(current.number)
-      if (current.prerequisite === maybeAncestor)
-        return true
-      current = all.find(i => i.number === current!.prerequisite)
-    }
-    return false
-  }
-
   function handleDragEnd(event: DragEndEvent): void {
     const { active, over } = event
     setActiveId(null)
     if (!over)
       return
 
-    const activeIdStr = String(active.id)
-    const overIdStr = String(over.id)
-    if (activeIdStr === overIdStr)
+    const result = resolveKanbanDrag({
+      issues,
+      activeId: String(active.id),
+      overId: String(over.id),
+    })
+
+    if (result.type === 'none')
       return
 
-    const activeIndex = issues.findIndex(i => i.id === activeIdStr)
-    if (activeIndex < 0)
+    if (result.type === 'reorder') {
+      onIssuesChange(arrayMove(issues, result.fromIndex, result.toIndex))
       return
-    const activeItem = issues[activeIndex]
-
-    // Lock check: a todo card whose prerequisite is still unfinished must
-    // stay in the todo column. Resolve target column from either the over
-    // column id or the over card's column.
-    const prereqIssue = activeItem.prerequisite != null
-      ? issues.find(i => i.number === activeItem.prerequisite)
-      : undefined
-    const isLocked = !!prereqIssue && prereqIssue.column !== 'done'
-    if (isLocked && activeItem.column === 'todo') {
-      const overItemForLock = isColumnId(overIdStr)
-        ? undefined
-        : issues.find(i => i.id === overIdStr)
-      const targetColumn: IssueColumn | undefined = isColumnId(overIdStr)
-        ? overIdStr
-        : overItemForLock?.column
-      if (targetColumn && targetColumn !== 'todo')
-        return
     }
 
-    // Dropped onto a column container
-    if (isColumnId(overIdStr)) {
-      // Drop onto the todo column's empty area while the card is already in
-      // todo → clear prerequisite (move to root level, append at column end).
-      if (overIdStr === 'todo' && activeItem.column === 'todo' && activeItem.prerequisite != null) {
-        const prevPrereq = activeItem.prerequisite
-        const next = [...issues]
-        next.splice(activeIndex, 1)
-        next.push({ ...activeItem, prerequisite: undefined })
-        onIssuesChange(next)
-        onDependencyClear?.(activeItem.number, prevPrereq)
-        return
-      }
-      if (activeItem.column === overIdStr)
+    if (result.type === 'column') {
+      const idx = issues.findIndex(i => i.number === result.issueNumber)
+      if (idx < 0)
         return
+      const item = issues[idx]
       const next = [...issues]
-      next.splice(activeIndex, 1)
-      next.push({ ...activeItem, column: overIdStr })
+      next.splice(idx, 1)
+      const overIdx = isColumnId(String(over.id))
+        ? -1
+        : next.findIndex(i => i.id === String(over.id))
+      const insertAt = overIdx < 0 ? next.length : overIdx
+      next.splice(insertAt, 0, { ...item, column: result.toColumn })
       onIssuesChange(next)
-      onColumnChange?.(activeItem.number, overIdStr, activeItem.source, activeItem.externalId)
+      onColumnChange?.(result.issueNumber, result.toColumn, result.source, result.externalId)
       return
     }
 
-    // Dropped onto another card
-    const overIndex = issues.findIndex(i => i.id === overIdStr)
-    if (overIndex < 0)
-      return
-    const overItem = issues[overIndex]
-
-    // Cross-column or non-todo-to-non-todo: keep the existing semantics.
-    if (activeItem.column !== 'todo' || overItem.column !== 'todo') {
-      if (activeItem.column === overItem.column) {
-        onIssuesChange(arrayMove(issues, activeIndex, overIndex))
+    if (result.type === 'dependency-set') {
+      const idx = issues.findIndex(i => i.number === result.issueNumber)
+      if (idx < 0)
         return
-      }
-      // Cross-column: drop activeItem at overItem's position in the new column
+      const item = issues[idx]
       const next = [...issues]
-      next.splice(activeIndex, 1)
-      const newOverIndex = next.findIndex(i => i.id === overIdStr)
-      const insertAt = newOverIndex < 0 ? next.length : newOverIndex
-      next.splice(insertAt, 0, { ...activeItem, column: overItem.column })
+      next.splice(idx, 1)
+      const overIdx = next.findIndex(i => i.number === result.prerequisiteNumber)
+      const insertAt = overIdx < 0 ? next.length : overIdx + 1
+      next.splice(insertAt, 0, { ...item, prerequisite: result.prerequisiteNumber })
       onIssuesChange(next)
-      onColumnChange?.(activeItem.number, overItem.column, activeItem.source, activeItem.externalId)
+      onDependencySet?.(result.issueNumber, result.prerequisiteNumber)
       return
     }
 
-    // Both in todo: distinguish nest (middle 1/3) vs sibling reorder (edge).
-    const zone = detectDropZone(event)
-    if (zone === 'middle') {
-      // Don't allow nesting onto our own descendant (would form a cycle).
-      if (isDescendant(activeItem.number, overItem.number, issues))
-        return
-      // Already nested under this same parent → nothing to do.
-      if (activeItem.prerequisite === overItem.number)
-        return
-      const next = [...issues]
-      next.splice(activeIndex, 1)
-      const newOverIndex = next.findIndex(i => i.id === overIdStr)
-      const insertAt = newOverIndex < 0 ? next.length : newOverIndex + 1
-      next.splice(insertAt, 0, { ...activeItem, prerequisite: overItem.number })
-      onIssuesChange(next)
-      onDependencySet?.(activeItem.number, overItem.number)
+    const idx = issues.findIndex(i => i.number === result.issueNumber)
+    if (idx < 0)
       return
-    }
-
-    // edge: sibling reorder. Inherit the over card's prerequisite as parent.
-    const newParent = overItem.prerequisite
-    if (newParent === activeItem.prerequisite) {
-      // Same parent (including both undefined): pure reorder.
-      onIssuesChange(arrayMove(issues, activeIndex, overIndex))
-      return
-    }
-    // Cycle guard: refuse to set the new parent if it would put active under
-    // its own descendant. Still reorder visually.
-    const cycle = newParent != null && isDescendant(activeItem.number, newParent, issues)
-    if (cycle) {
-      onIssuesChange(arrayMove(issues, activeIndex, overIndex))
-      return
-    }
+    const item = issues[idx]
     const next = [...issues]
-    next.splice(activeIndex, 1)
-    const newOverIndex = next.findIndex(i => i.id === overIdStr)
-    const insertAt = newOverIndex < 0 ? next.length : newOverIndex
-    next.splice(insertAt, 0, { ...activeItem, prerequisite: newParent })
+    next.splice(idx, 1)
+    next.push({ ...item, prerequisite: undefined })
     onIssuesChange(next)
-    if (newParent == null)
-      onDependencyClear?.(activeItem.number, activeItem.prerequisite!)
-    else
-      onDependencySet?.(activeItem.number, newParent)
+    onDependencyClear?.(result.issueNumber, result.prerequisiteNumber)
   }
 
   return (
     <DndContext
       sensors={sensors}
+      collisionDetection={kanbanCollisionDetection}
       onDragStart={handleDragStart}
       onDragEnd={handleDragEnd}
       onDragCancel={() => setActiveId(null)}
diff --git a/vscode/webview-ui/src/lib/kanbanDrag.test.ts b/vscode/webview-ui/src/lib/kanbanDrag.test.ts
new file mode 100644
index 0000000..3e40928
--- /dev/null
+++ b/vscode/webview-ui/src/lib/kanbanDrag.test.ts
@@ -0,0 +1,120 @@
+import type { Issue, IssueColumn } from '../types'
+import { describe, expect, it } from 'vitest'
+import { isColumnId, resolveKanbanDrag } from './kanbanDrag'
+
+function issue(
+  number: number,
+  column: IssueColumn,
+  extra: Partial<Issue> = {},
+): Issue {
+  return {
+    id: `repo#${number}`,
+    number,
+    title: `issue ${number}`,
+    column,
+    htmlUrl: '',
+    ...extra,
+  }
+}
+
+describe('isColumnId', () => {
+  it('识别四列 id', () => {
+    expect(isColumnId('todo')).toBe(true)
+    expect(isColumnId('in-progress')).toBe(true)
+    expect(isColumnId('review')).toBe(true)
+    expect(isColumnId('done')).toBe(true)
+  })
+
+  it('拒绝卡片 id', () => {
+    expect(isColumnId('repo#1')).toBe(false)
+  })
+})
+
+describe('resolveKanbanDrag', () => {
+  it('active===over → none', () => {
+    const issues = [issue(1, 'todo')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#1' }))
+      .toEqual({ type: 'none' })
+  })
+
+  it('丢到另一张待办卡片 = set（over 为前置）', () => {
+    const issues = [issue(1, 'todo'), issue(2, 'todo')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#2' }))
+      .toEqual({ type: 'dependency-set', issueNumber: 1, prerequisiteNumber: 2 })
+  })
+
+  it('丢到待办列空白且已有依赖 = clear', () => {
+    const issues = [issue(1, 'todo', { prerequisite: 2 }), issue(2, 'todo')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'todo' }))
+      .toEqual({ type: 'dependency-clear', issueNumber: 1, prerequisiteNumber: 2 })
+  })
+
+  it('over 是列且已在 todo 且无依赖 = none', () => {
+    const issues = [issue(1, 'todo')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'todo' }))
+      .toEqual({ type: 'none' })
+  })
+
+  it('跨列仍是 column', () => {
+    const issues = [issue(1, 'in-progress'), issue(2, 'todo')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'todo' }))
+      .toEqual({ type: 'column', issueNumber: 1, toColumn: 'todo' })
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#2' }))
+      .toEqual({ type: 'column', issueNumber: 1, toColumn: 'todo' })
+  })
+
+  it('跨列带上 source / externalId', () => {
+    const issues = [issue(1, 'review', { source: 'youtrack', externalId: 'LXF-1' })]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'todo' }))
+      .toEqual({
+        type: 'column',
+        issueNumber: 1,
+        toColumn: 'todo',
+        source: 'youtrack',
+        externalId: 'LXF-1',
+      })
+  })
+
+  it('环拒绝：不能把祖先挂到自己的后代下', () => {
+    const issues = [
+      issue(1, 'todo'),
+      issue(2, 'todo', { prerequisite: 1 }),
+      issue(3, 'todo', { prerequisite: 2 }),
+    ]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#3' }))
+      .toEqual({ type: 'none' })
+  })
+
+  it('已经是这个 parent → none', () => {
+    const issues = [issue(1, 'todo', { prerequisite: 2 }), issue(2, 'todo')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#2' }))
+      .toEqual({ type: 'none' })
+  })
+
+  it('换 parent 也是 dependency-set，不先 clear', () => {
+    const issues = [
+      issue(1, 'todo', { prerequisite: 2 }),
+      issue(2, 'todo'),
+      issue(3, 'todo'),
+    ]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#3' }))
+      .toEqual({ type: 'dependency-set', issueNumber: 1, prerequisiteNumber: 3 })
+  })
+
+  it('同列非 todo → reorder', () => {
+    const issues = [issue(1, 'in-progress'), issue(2, 'in-progress')]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#2' }))
+      .toEqual({ type: 'reorder', fromIndex: 0, toIndex: 1 })
+  })
+
+  it('锁定：todo 且前置未完成，目标列不是 todo → none', () => {
+    const issues = [
+      issue(1, 'todo', { prerequisite: 2 }),
+      issue(2, 'in-progress'),
+    ]
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'in-progress' }))
+      .toEqual({ type: 'none' })
+    expect(resolveKanbanDrag({ issues, activeId: 'repo#1', overId: 'repo#2' }))
+      .toEqual({ type: 'none' })
+  })
+})
diff --git a/vscode/webview-ui/src/lib/kanbanDrag.ts b/vscode/webview-ui/src/lib/kanbanDrag.ts
new file mode 100644
index 0000000..1b0d9d3
--- /dev/null
+++ b/vscode/webview-ui/src/lib/kanbanDrag.ts
@@ -0,0 +1,102 @@
+import type { Issue, IssueColumn } from '../types'
+import { COLUMN_ORDER } from '../types'
+import { isIssueLocked } from './dependencies'
+
+export function isColumnId(id: string): id is IssueColumn {
+  return (COLUMN_ORDER as string[]).includes(id)
+}
+
+export type KanbanDragResult
+  = | { type: 'none' }
+    | { type: 'column', issueNumber: number, toColumn: IssueColumn, source?: 'gitea' | 'youtrack', externalId?: string }
+    | { type: 'dependency-set', issueNumber: number, prerequisiteNumber: number }
+    | { type: 'dependency-clear', issueNumber: number, prerequisiteNumber: number }
+    | { type: 'reorder', fromIndex: number, toIndex: number }
+
+function isDescendant(maybeAncestor: number, target: number, all: Issue[]): boolean {
+  const visited = new Set<number>()
+  let current: Issue | undefined = all.find(i => i.number === target)
+  while (current && current.prerequisite != null) {
+    if (visited.has(current.number))
+      return false
+    visited.add(current.number)
+    if (current.prerequisite === maybeAncestor)
+      return true
+    current = all.find(i => i.number === current!.prerequisite)
+  }
+  return false
+}
+
+export function resolveKanbanDrag(opts: {
+  issues: Issue[]
+  activeId: string
+  overId: string
+}): KanbanDragResult {
+  const { issues, activeId, overId } = opts
+  if (activeId === overId)
+    return { type: 'none' }
+
+  const activeItem = issues.find(i => i.id === activeId)
+  if (!activeItem)
+    return { type: 'none' }
+
+  // ① 锁：待办且前置未完成，只能在 todo 列内操作
+  const locked = isIssueLocked(activeItem, issues).locked && activeItem.column === 'todo'
+  const overIsColumn = isColumnId(overId)
+  const overItem = overIsColumn ? undefined : issues.find(i => i.id === overId)
+  const targetColumn: IssueColumn | undefined = overIsColumn ? overId : overItem?.column
+  if (locked && targetColumn && targetColumn !== 'todo')
+    return { type: 'none' }
+
+  // ② over 是列：已在 todo 且有依赖 → 清依赖；已在该列 → none；否则换列
+  if (overIsColumn) {
+    if (overId === 'todo' && activeItem.column === 'todo' && activeItem.prerequisite != null) {
+      return {
+        type: 'dependency-clear',
+        issueNumber: activeItem.number,
+        prerequisiteNumber: activeItem.prerequisite,
+      }
+    }
+    if (activeItem.column === overId)
+      return { type: 'none' }
+    return {
+      type: 'column',
+      issueNumber: activeItem.number,
+      toColumn: overId,
+      ...(activeItem.source ? { source: activeItem.source } : {}),
+      ...(activeItem.externalId ? { externalId: activeItem.externalId } : {}),
+    }
+  }
+
+  if (!overItem)
+    return { type: 'none' }
+
+  // ③ over 是卡片：双方 todo → 设依赖；同列非 todo → 重排；跨列 → 换列
+  if (activeItem.column === 'todo' && overItem.column === 'todo') {
+    if (isDescendant(activeItem.number, overItem.number, issues))
+      return { type: 'none' }
+    if (activeItem.prerequisite === overItem.number)
+      return { type: 'none' }
+    return {
+      type: 'dependency-set',
+      issueNumber: activeItem.number,
+      prerequisiteNumber: overItem.number,
+    }
+  }
+
+  if (activeItem.column === overItem.column) {
+    return {
+      type: 'reorder',
+      fromIndex: issues.findIndex(i => i.id === activeId),
+      toIndex: issues.findIndex(i => i.id === overId),
+    }
+  }
+
+  return {
+    type: 'column',
+    issueNumber: activeItem.number,
+    toColumn: overItem.column,
+    ...(activeItem.source ? { source: activeItem.source } : {}),
+    ...(activeItem.externalId ? { externalId: activeItem.externalId } : {}),
+  }
+}
diff --git a/vscode/webview-ui/src/lib/messages.ts b/vscode/webview-ui/src/lib/messages.ts
index dad7544..2db3ffb 100644
--- a/vscode/webview-ui/src/lib/messages.ts
+++ b/vscode/webview-ui/src/lib/messages.ts
@@ -57,7 +57,7 @@ export type ExtensionToWebview
   = | { type: 'issues/loading' }
     | { type: 'issues/update', issues: Issue[], scope: 'mine' | 'all', globalAutoReview: boolean, youtrackConfigured: boolean }
     | { type: 'issues/error', message: string }
-    | { type: 'issue/patch', issueNumber: number, patch: { autoReview?: boolean, specFile?: string, planFile?: string, prDiffFile?: string, sessionId?: string, implementSessionId?: string, reviewSessionId?: string, reviewSessionFileExists?: boolean, testSessionId?: string, pr?: string | null, implementStatus?: 'running' | 'done' | 'failed', column?: IssueColumn, worktreePath?: string | null, prMerged?: boolean, prMergedAt?: string, branch?: string | null, color?: string, worktreeExists?: boolean, brainstormTabOpen?: boolean, implementTabOpen?: boolean, reviewTabOpen?: boolean, testTabOpen?: boolean, profilePath?: string, brainstormProfilePath?: string, testProfilePath?: string } }
+    | { type: 'issue/patch', issueNumber: number, patch: { autoReview?: boolean, specFile?: string, planFile?: string, prDiffFile?: string, sessionId?: string, implementSessionId?: string | null, reviewSessionId?: string | null, reviewSessionFileExists?: boolean, testSessionId?: string, pr?: string | null, implementStatus?: 'running' | 'done' | 'failed' | null, column?: IssueColumn, worktreePath?: string | null, prMerged?: boolean, prMergedAt?: string | null, branch?: string | null, color?: string, worktreeExists?: boolean, brainstormTabOpen?: boolean, implementTabOpen?: boolean, reviewTabOpen?: boolean, testTabOpen?: boolean, profilePath?: string, brainstormProfilePath?: string, testProfilePath?: string } }
     | { type: 'issue/pr-diff-summary-done', issueNumber: number }
     | { type: 'issue/append', issue: Issue, select?: boolean }
     | { type: 'issue/select-by-number', issueNumber: number }
diff --git a/vscode/webview-ui/tsconfig.json b/vscode/webview-ui/tsconfig.json
index 94490b9..02ad2f2 100644
--- a/vscode/webview-ui/tsconfig.json
+++ b/vscode/webview-ui/tsconfig.json
@@ -20,5 +20,6 @@
     }
   },
   "include": ["src"],
+  "exclude": ["src/**/*.test.ts"],
   "references": [{ "path": "./tsconfig.node.json" }]
 }