Add live annotate file tree workspace status

[backnotprop]

Summary

• add Git-backed workspace status to annotate file trees, including added/deleted/renamed/untracked markers and +/- counts
• add debounced Chokidar/SSE file-tree invalidation for Bun and Pi servers, using one multiplexed stream for multiple roots
• keep source-file direct-edit cards out of the annotation panel until edits are saved to disk, then show saved edits as context

Verification

• bun test packages/server/reference-watch.test.ts packages/shared/workspace-status.test.ts packages/server/reference-handlers.test.ts apps/pi-extension/server.test.ts packages/editor/directEdits.test.ts packages/ui/annotationDraftPersistence.test.tsx
• bun run typecheck
• bun run build:hook
• bun run build:review
• git diff --check