✨ feat(vscode): 新增第五种工单会话「原型会话」

照测试会话那条链路补一份 prototype：

- 消息与路由：session/start-prototype、session/resume-prototype、
  issue/update-prototype-profile-path，都进只读门禁
- 会话：handleStartPrototypeSession / handleResumePrototypeSession，
  终端名 issue-N-原型；cwd 有 worktree 用 worktree、没有退主仓库根
  （原 resolveTestSessionCwd 改名 resolveWorktreeOrRootCwd 两种会话共用）
- 不要求有 PR，任何阶段都能起；前置工单锁仍然拦
- 提示词：新增 prompts/prototype.md，设置里可改，占位符 {issueNumber}
- profile：工单级 prototypeProfilePath > 设置里的原型默认 profile >
  内置默认，与其它会话互不回退
- 状态字段 prototypeSessionId / prototypeProfilePath / prototypeTabOpen
  贯通 gitea、youtrack、本机 state 与移交包
- 详情面板加「原型会话id」「原型配置文件」两行，设置面板加对应两项

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

vscode/src/panel/handlers/issues.ts

@@ -117,6 +117,7 @@ export async function handleColumnChange(panel: KanbanWebviewPanel, issueNumber:
   let fromColumn: IssueColumn | undefined
   let implementSessionId: string | undefined
   let testSessionId: string | undefined
+  let prototypeSessionId: string | undefined
   let featureBranchFromState: string | undefined
   try {
     const stateObj = await panel.readIssueState(issueNumber)
@@ -134,6 +135,8 @@ export async function handleColumnChange(panel: KanbanWebviewPanel, issueNumber:
       implementSessionId = stateObj.implementSessionId
     if (typeof stateObj.testSessionId === 'string' && stateObj.testSessionId.length > 0)
       testSessionId = stateObj.testSessionId
+    if (typeof stateObj.prototypeSessionId === 'string' && stateObj.prototypeSessionId.length > 0)
+      prototypeSessionId = stateObj.prototypeSessionId
     if (typeof stateObj.branch === 'string' && stateObj.branch.length > 0)
       featureBranchFromState = stateObj.branch
   }
@@ -394,13 +397,13 @@ export async function handleColumnChange(panel: KanbanWebviewPanel, issueNumber:
     issueNumber,
   })
 
-  // 删 worktree 前把实施/测试会话整包（jsonl + 子目录）搬到主仓库 projects 目录，
+  // 删 worktree 前把实施/测试/原型会话整包（jsonl + 子目录）搬到主仓库 projects 目录，
   // 并清掉 worktree 侧副本：新版 claude 遇到重复 sid 会拒绝 resume。
-  if ((implementSessionId || testSessionId) && worktreePath) {
+  if ((implementSessionId || testSessionId || prototypeSessionId) && worktreePath) {
     const worktreeAbs = resolveWorktreePath(worktreePath, workspaceRoot)
     const srcProjectsDir = projectsDirFor(worktreeAbs)
     const dstProjectsDir = projectsDirFor(workspaceRoot)
-    for (const sid of [implementSessionId, testSessionId]) {
+    for (const sid of [implementSessionId, testSessionId, prototypeSessionId]) {
       if (typeof sid !== 'string' || sid.length === 0)
         continue
       try {
@@ -2210,6 +2213,95 @@ export async function handleUpdateTestProfilePath(panel: KanbanWebviewPanel, iss
   }
 }
 
+/**
+ * Persist a per-issue `prototypeProfilePath` override into the issue's state JSON
+ * comment. 原型 start/resume 用它（见 resolvePrototypeProfilePath）；
+ * 空 = 设置里的「原型默认配置文件」，再空 = getDefaultProfilePath()，与其它会话互不回退。
+ */
+export async function handleUpdatePrototypeProfilePath(panel: KanbanWebviewPanel, issueNumber: number, prototypeProfilePath: string): Promise<void> {
+  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,
+    })
+    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,
+    })
+    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,
+    })
+    return
+  }
+
+  // Snapshot the previous value so we can roll the webview back on failure
+  // without re-broadcasting the whole issues list.
+  let previousValue: string | undefined
+  try {
+    const existingState = await panel.readIssueState(issueNumber)
+    previousValue = typeof existingState.prototypeProfilePath === 'string'
+      ? existingState.prototypeProfilePath
+      : undefined
+  }
+  catch {
+    // If we can't read the previous state, leave previousValue undefined —
+    // the rollback patch will clear the override, falling back to the default.
+    previousValue = undefined
+  }
+
+  try {
+    await panel.mergeIssueState(issueNumber, { prototypeProfilePath })
+    logger.add({
+      level: 'info',
+      source: 'panel',
+      message: `工单 #${issueNumber} prototypeProfilePath=${prototypeProfilePath} 已持久化`,
+    })
+  }
+  catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    logger.add({
+      level: 'error',
+      source: 'panel',
+      message: `持久化 prototypeProfilePath 失败 (issue #${issueNumber})`,
+      details: message,
+    })
+    panel.postMessage({
+      type: 'toast/show',
+      id: makeNonce(),
+      level: 'error',
+      message: `保存工单 #${issueNumber} 原型配置文件失败: ${message}`,
+      dismissOnTimer: 6000,
+    })
+    // Roll back the optimistic update in the webview.
+    panel.postMessage({
+      type: 'issue/patch',
+      issueNumber,
+      patch: { prototypeProfilePath: previousValue },
+    })
+  }
+}
+
 export async function handleOpenFile(panel: KanbanWebviewPanel, relPath: string): Promise<void> {
   const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
   if (!workspaceRoot) {