feat(composer): replicate WorkBuddy branch label and context usage (TODO 21)

src/shared/ipc.ts

@@ -10,7 +10,8 @@ import type {
   GatewayConfigView,
   WorkspaceInfo,
   WindowState,
-  AppInfo
+  AppInfo,
+  GitBranchInfo
 } from './types'
 import type { DownloadPayload, DownloadResult, ResourceEntry, ResourceRange, WorkspaceResource } from './resources'
 import type { ChatAttachment, InteractionResponse, MessageQuote, PermissionMode } from './conversation'
@@ -91,6 +92,10 @@ export interface YCodeApi {
     onSettingsChanged(listener: () => void): () => void
     onSettingsNavigate(listener: (section: string, action?: 'new') => void): () => void
   }
+  git: {
+    /** 读取某个会话工作目录的真实分支信息；目录不在仓库内或 git 不可用时返回 repo:false/unavailable。 */
+    branch(sessionId: string): Ipc<GitBranchInfo>
+  }
   config: {
     get(): Ipc<GatewayConfigView>
     update(patch: ConfigPatchLike): Ipc<GatewayConfigView>