✨ feat(vscode): 工单挂原型插件，详情面板一键导入 Figma

- prototypeFile 走通 state → Issue → webview 全链路（gitea/youtrack 两个
  loader、两份 KNOWN_STATE_FIELDS、issue/patch、webview types），按 planFile
  同款当共享字段；路径校验换成 .json 版，允许绝对路径
- 详情面板「计划文件」下加「原型插件路径」行：双击开 manifest.json，
  行尾按钮「在 Figma 中导入并打开」；没挂插件时只显示空态
- src/figma/：把 manifest 写进 Figma 桌面版的 localFileExtensions 再拉起
  Figma。坑是 Figma 退出会用内存状态覆盖 settings.json，所以写之前先
  osascript 优雅退出并轮询等它真没了（10s 等不到就让用户手动关，不强杀）；
  写前备份 settings.json.bak-<时间戳>；已导入过就跳过写入直接打开；
  非 macOS 只把路径复制到剪贴板
- webhook 里 spec/plan 的 marker 同步改成表驱动，顺带认第三种 prototype
- 提示词：prototype.md 要求画完挂 marker；brainstorm-continue.md 新增
  {prototypeRef} 占位符，有原型插件时让续聊先读它别从零重画，没有时
  连同整段抹掉

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

vscode/webview-ui/src/components/IssueDetailPanel.tsx

@@ -69,6 +69,11 @@ interface IssueDetailPanelProps {
   onStartPrototypeSession: (issueNumber: number) => void
   /** Open a workspace-relative file in the editor. */
   onOpenFile: (path: string) => void
+  /**
+   * 把工单的 Figma 插件 manifest 导进本机 Figma 桌面版并拉起 Figma。
+   * 「原型插件路径」行尾那个按钮。
+   */
+  onOpenPrototypeInFigma: (issueNumber: number, path: string) => void
   /** Kick off the end-to-end implementation flow for the given plan file. */
   onImplement: (issueNumber: number, planFile: string, profilePath?: string, sessionId?: string) => void
   /** Open the gitea PR page in the browser. */
@@ -151,6 +156,7 @@ export function IssueDetailPanel({
   onStartTestSession,
   onStartPrototypeSession,
   onOpenFile,
+  onOpenPrototypeInFigma,
   onImplement,
   onOpenPr,
   onGeneratePrDiffSummary,
@@ -567,6 +573,24 @@ export function IssueDetailPanel({
                 }]
               : [],
           },
+          {
+            key: 'prototypeFile',
+            label: '原型插件路径',
+            type: 'file-link',
+            description: '双击在编辑器打开 Figma 插件的 manifest.json；点右侧按钮把插件导入本机 Figma 并打开；cc 通过 issue body 的 <!-- spx:prototype=路径 --> 注释同步',
+            onOpen: (p: string) => onOpenFile(p),
+            // 没挂原型插件时整个按钮不渲染，行只显示空态。
+            secondaryActions: issue?.prototypeFile
+              ? [{
+                  icon: <ExternalLink className="size-3.5" />,
+                  title: '在 Figma 中导入并打开',
+                  onClick: () => {
+                    if (issue?.prototypeFile)
+                      onOpenPrototypeInFigma(issue.number, issue.prototypeFile)
+                  },
+                }]
+              : [],
+          },
           {
             key: 'pr',
             label: '合并请求',
@@ -641,7 +665,7 @@ export function IssueDetailPanel({
         ],
       },
     ],
-    [onResumeSession, onResumeReviewSession, onResumeTestSession, onStartTestSession, onResumePrototypeSession, onStartPrototypeSession, onOpenFile, onImplement, onOpenPr, onGeneratePrDiffSummary, onOpenWorktree, onDeleteWorktree, onMergeBranch, onCloseSessionTab, onContinueBrainstorm, onClearBrainstormSession, onOpenLogs, issue, locked, lockTitle, globalAutoReview, prDiffSummaryRunning, profiles, isSessionTabPending, onStartReviewSession],
+    [onResumeSession, onResumeReviewSession, onResumeTestSession, onStartTestSession, onResumePrototypeSession, onStartPrototypeSession, onOpenFile, onOpenPrototypeInFigma, onImplement, onOpenPr, onGeneratePrDiffSummary, onOpenWorktree, onDeleteWorktree, onMergeBranch, onCloseSessionTab, onContinueBrainstorm, onClearBrainstormSession, onOpenLogs, issue, locked, lockTitle, globalAutoReview, prDiffSummaryRunning, profiles, isSessionTabPending, onStartReviewSession],
   )
 
   // 同事的工单只读：属性表统一消毒，顶部只留查看类按钮。
@@ -671,6 +695,7 @@ export function IssueDetailPanel({
       prototypeProfilePath: matchProfileOption(issue.prototypeProfilePath, profiles) || null,
       specFile: issue.specFile ?? null,
       planFile: issue.planFile ?? null,
+      prototypeFile: issue.prototypeFile ?? null,
       prDiffFile: issue.prDiffFile ?? null,
       pr: issue.pr
         ? `${issue.pr}${issue.prMerged ? '(已合并)' : ''}`