feat(runtime-api): expose thread branch metadata

Add read-only workspace and branch metadata to runtime thread summaries so VS Code Agent View can show when a thread lane is on another branch. Non-git workspaces return null branch metadata instead of failing.

Refs #2580, #2721.
Credits the existing branch-visibility trail from #1217/#2341 in the changelog.

extensions/vscode/out/runtime.js

@@ -184,6 +184,8 @@ function readThreadSummaries(value) {
                 preview: readString(record.preview) ?? "",
                 model: readString(record.model) ?? "unknown",
                 mode: readString(record.mode) ?? "agent",
+                workspace: readString(record.workspace),
+                branch: readString(record.branch),
                 archived: record.archived === true,
                 updatedAt: readString(record.updated_at) ?? "",
                 latestTurnStatus: readString(record.latest_turn_status),