feat(FN-4137): add review markdown toggle to document view (FN-4137)

This large merge delivers substantial improvements across the dashboard, engine, and CI infrastructure. Key themes include GitHub tracking feature parity (mobile layout, card icons, header alignment, title derivation, restart persistence, untitled issue handling), chat/room UX enhancements (draft au

Fusion-Task-Id: FN-4137

docs/storage.md

@@ -47,6 +47,21 @@ The script checks for:
 
 Treat flagged candidates as recovery leads, not automatic truth: review the surviving task files, logs, and commit history, then file a follow-up recovery task for any confirmed overwrite.
 
+### Reconciling stale task title/description vs canonical PROMPT.md
+
+Use the one-shot reconciliation script only when the surviving evidence agrees on a single canonical task identity and the ambiguity is limited to stale metadata fields on that same task row:
+
+```bash
+node scripts/reconcile-fn-3909-identity.mjs [--project-root /path/to/project] [--apply]
+```
+
+The script is intentionally narrow and idempotent:
+- dry-run is the default and prints the before/after title + description diff without mutating anything
+- `--apply` only updates task `FN-3909` through `TaskStore.updateTask(...)` and appends an audit log entry referencing `FN-4194`
+- the script refuses to run if `PROMPT.md` no longer matches the expected canonical heading, if the stale heartbeat-scope row contents are not present, or if the row is already canonical without the reconciliation marker
+
+Use this path for the confirmed FN-3909 mismatch (canonical UI-fix prompt/merge history, stale heartbeat-scope title/description). Do **not** use it for allocator-collision or overwrite incidents that may involve multiple tasks or conflicting survivors; run `scripts/audit-task-id-collisions.mjs` first and treat those cases as recovery/postmortem work instead of automatic metadata repair.
+
 ## SQLite write-path lock recovery (FN-4042 / FN-4083)
 
 - Every disk-backed SQLite connection that Fusion opens for project storage (`fusion.db`), the central registry (`fusion-central.db`), archives (`archive.db`), and worktree hydration explicitly sets `PRAGMA busy_timeout = 5000` and `PRAGMA journal_mode = WAL` at connection open time before write work begins.

docs/task-management.md

@@ -330,6 +330,7 @@ This file is the contract for execution and review.
   - Pull-request mode refreshes live GitHub-backed review decision/thread/comment state and updates PR metadata freshness.
   - Direct/non-PR mode refreshes normalized reviewer-agent feedback from persisted task review artifacts and does not call GitHub.
 - In direct/non-PR auto-merge mode, the Review tab shows parsed reviewer-agent feedback with explicit loading/error/empty states instead of sending users to raw comments or agent logs.
+- Review item bodies render markdown by default, and users can switch between **Markdown** and **Plain** modes from the Review tab action bar; the preference persists locally per user.
 - **Comments remains the general discussion surface**; Review remains the actionable review surface.
 - **Steering comments** (`fn task steer`) are execution guidance for the running agent.