Parent

Spec: specs/pr-devserver-review.md — see Revision 2 (R2.2): relay = reviewer's own local board app, reviewer's own identity. Repo: backend.ai-webui (overlay Vite plugin).

What to build

On a running webui dev server, a reviewer toggles comment mode, clicks an element, writes a comment — it lands as a reply in the PR's real Teams thread as the reviewer's own Teams account (no attribution prefix), with a #bai-review= deep-link. Replies made in the Teams app show up in the overlay's chat panel within ~15 s, and the reviewer receives native reply notifications (they are a real thread participant). Narrow on purpose: selector-only anchor, no screenshots, thread URL supplied manually, minimal styling.

Acceptance criteria

• Dev-only Vite plugin (transformIndexHtml) injects a Shadow-DOM overlay served same-origin as a virtual module; zero effect on production builds
• Element pick (hover outline → click) drops a numbered pin; compose posts to the reviewer's own local board relay (http://localhost:7777/api/…, CORS — Rev 2), NOT to dev-server middleware
• Relay auth reuses the fw TEAMS_CLIENT_ID MSAL cache (silent); posts appear as the reviewer's real account; message carries dev-URL deep link with #bai-review= fragment
• Overlay handles relay-unavailable (connection refused / 401) with a "run board serve" hint
• Chat panel polls thread replies (10–15 s) and renders them; pin ↔ message highlight
• Demo: pin comment → visible in Teams under the reviewer's name; Teams reply → visible in panel + native notification received

Blocked by

• "Local board app" (FR-3306) — the relay the overlay posts to lives there (Rev 2)

JIRA Issue: FR-3309