⚡ perf(vscode): 开会话去掉多余远程往返，spinner 跟随真实进度

开会话原先要先全量拉工单（含每张工单的评论、依赖、PR）做前置锁检查，
再各读一次 state JSON 给 pre-create 钩子和终端图标，几秒后才 createTerminal。

- 锁检查改用主进程已算好的工单快照，快照里没有该工单才回落全量拉取
- state JSON 一次读两处用，且提前发起与本地准备重叠
- 会话行 spinner 由扩展的 session/tab-settled 消息驱动，不再是固定 1.5s 假动画，
  消息丢失时 60s 超时兜底

Claude-Session: https://claude.ai/code/session_01Kgmb1LvrPmFX3NoUDB4zZC

vscode/src/panel/handlers/issues.ts

@@ -1,4 +1,5 @@
 import type { IssueColumn } from '../../gitea/types'
+import type { LockedReason } from '../issueLock'
 import type { KanbanWebviewPanel } from '../KanbanPanel'
 import { Buffer } from 'node:buffer'
 import { randomUUID } from 'node:crypto'
@@ -35,6 +36,7 @@ import { logger } from '../../logging/logger'
 import { getEffectivePrDiffSummaryProfilePath, getSettings } from '../../settings/store'
 import { webhookCoordinator } from '../../webhook/coordinator'
 import { pickRandomIssueColor, themeColorIdToIconUri } from '../issueColor'
+import { evaluateLockedReason } from '../issueLock'
 import { makeNonce } from '../KanbanPanel'
 import { cleanupFeatureBranch } from './branchCleanup'
 import * as sessions from './sessions'
@@ -1572,12 +1574,10 @@ export async function syncCloseGiteaIssue(panel: KanbanWebviewPanel, opts: {
 }
 
 /**
- * Server-side lock check for prerequisite gating. Fetches a fresh issues
- * snapshot (we don't trust webview state) and reports whether
- * `issueNumber` is blocked by an unfinished prerequisite. Mirrors the
- * webview-side `isIssueLocked` predicate: locked iff the issue has a
- * prerequisite that exists in the current snapshot and is not yet in the
- * `done` column.
+ * Server-side lock check for prerequisite gating（不信 webview 传来的状态）。
+ * 优先用主进程自己算好的工单快照——开会话是热路径，全量 loadIssues 要拉工单
+ * 列表、每张工单的评论、依赖和 PR，几秒起步；快照没有该工单（面板还没加载
+ * 完）时才退回一次全量拉取。
  *
  * Fail-open: any error fetching issues is logged and we return
  * `{ locked: false }` so a transient Gitea hiccup can't lock the user out
@@ -1586,8 +1586,12 @@ export async function syncCloseGiteaIssue(panel: KanbanWebviewPanel, opts: {
 export async function resolveLockedReason(
   panel: KanbanWebviewPanel,
   issueNumber: number,
-): Promise<{ locked: boolean, prerequisiteNumber?: number, prerequisiteColumn?: string }> {
+): Promise<LockedReason> {
   try {
+    const snapshot = panel.snapshotIssues()
+    if (snapshot?.some(i => i.number === issueNumber))
+      return evaluateLockedReason(snapshot, issueNumber)
+
     const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
     if (!workspaceRoot)
       return { locked: false }
@@ -1604,21 +1608,7 @@ export async function resolveLockedReason(
       repo: remote.repo,
       workspaceRoot,
     })
-    const issue = issues.find(i => i.number === issueNumber)
-    if (!issue)
-      return { locked: false }
-    if (issue.prerequisite === undefined)
-      return { locked: false }
-    const prereq = issues.find(i => i.number === issue.prerequisite)
-    if (!prereq)
-      return { locked: false }
-    if (prereq.column === 'done')
-      return { locked: false }
-    return {
-      locked: true,
-      prerequisiteNumber: prereq.number,
-      prerequisiteColumn: prereq.column,
-    }
+    return evaluateLockedReason(issues, issueNumber)
   }
   catch (err) {
     const message = err instanceof Error ? err.message : String(err)