✨ 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/messages.ts

@@ -52,7 +52,7 @@ export type ExtensionToWebview
     | { type: 'issues/loaded' }
     | { type: 'issues/update', issues: Issue[], scope: 'mine' | 'all', globalAutoReview: boolean, youtrackConfigured: boolean, me?: string, avatars?: Record<string, string> }
     | { type: 'issues/error', message: string }
-    | { type: 'issue/patch', issueNumber: number, patch: { autoReview?: boolean, specFile?: string, planFile?: string, prDiffFile?: string | null, sessionId?: string | null, implementSessionId?: string | null, reviewSessionId?: string | null, reviewSessionFileExists?: boolean, testSessionId?: string | null, 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 | null, brainstormProfilePath?: string | null, testProfilePath?: string | null, assignees?: string[], handoffAttachmentId?: string | null, handoffFrom?: string | null } }
+    | { type: 'issue/patch', issueNumber: number, patch: { autoReview?: boolean, specFile?: string, planFile?: string, prDiffFile?: string | null, sessionId?: string | null, implementSessionId?: string | null, reviewSessionId?: string | null, reviewSessionFileExists?: boolean, testSessionId?: string | null, prototypeSessionId?: string | null, 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, prototypeTabOpen?: boolean, profilePath?: string | null, brainstormProfilePath?: string | null, testProfilePath?: string | null, prototypeProfilePath?: string | null, assignees?: string[], handoffAttachmentId?: string | null, handoffFrom?: string | null } }
     /** 某个会话 id 的开 tab 请求已处理完（开成、复用或被拒都算），webview 据此停掉行内 spinner。 */
     | { type: 'session/tab-settled', sessionId: string }
     | { type: 'issue/pr-diff-summary-done', issueNumber: number }
@@ -77,6 +77,7 @@ export type ExtensionToWebview
       autoReview: boolean
       reviewPrompt: string
       testPrompt: string
+      prototypePrompt: string
       devBranch: string
       releaseBranchPrefix: string
       jenkinsJob: string
@@ -92,6 +93,7 @@ export type ExtensionToWebview
       defaultBrainstormProfilePath: string
       defaultImplementProfilePath: string
       defaultTestProfilePath: string
+      defaultPrototypeProfilePath: string
       conflictResolutionProfilePath: string
       commitProfilePath: string
       prDiffSummaryProfilePath: string
@@ -160,6 +162,7 @@ export type WebviewToExtension
       autoReview: boolean
       reviewPrompt: string
       testPrompt: string
+      prototypePrompt: string
       devBranch: string
       releaseBranchPrefix: string
       jenkinsJob: string
@@ -175,6 +178,7 @@ export type WebviewToExtension
       defaultBrainstormProfilePath: string
       defaultImplementProfilePath: string
       defaultTestProfilePath: string
+      defaultPrototypeProfilePath: string
       conflictResolutionProfilePath: string
       commitProfilePath: string
       prDiffSummaryProfilePath: string
@@ -195,8 +199,10 @@ export type WebviewToExtension
     | { type: 'session/focus', issueNumber: number }
     | { type: 'session/resume-review', sessionId: string, issueNumber: number, cwd?: string }
     | { type: 'session/resume-test', sessionId: string, issueNumber: number, cwd?: string }
+    | { type: 'session/resume-prototype', sessionId: string, issueNumber: number, cwd?: string }
     | { type: 'session/start-review', issueNumber: number }
     | { type: 'session/start-test', issueNumber: number }
+    | { type: 'session/start-prototype', issueNumber: number }
     | { type: 'editor/open-file', path: string }
     | { type: 'profiles/list' }
     | { type: 'issue/implement', issueNumber: number, planFile: string, profilePath?: string, sessionId?: string }
@@ -220,10 +226,11 @@ export type WebviewToExtension
     | { type: 'issue/update-brainstorm-profile-path', issueNumber: number, brainstormProfilePath: string }
     | { type: 'issue/clear-brainstorm-session', issueNumber: number }
     | { type: 'issue/update-test-profile-path', issueNumber: number, testProfilePath: string }
+    | { type: 'issue/update-prototype-profile-path', issueNumber: number, prototypeProfilePath: string }
     | { type: 'logs/fetch' }
     | { type: 'logs/clear' }
     | { type: 'commit/run' }
-    | { type: 'session/close-tab', issueNumber: number, kind: 'brainstorm' | 'implement' | 'review' | 'test' }
+    | { type: 'session/close-tab', issueNumber: number, kind: 'brainstorm' | 'implement' | 'review' | 'test' | 'prototype' }
     | { type: 'release/check' }
     | { type: 'release/cut' }
     | { type: 'release/cherry-pick' }