todo: record shipped email work and deferred follow-ups

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

TODO.md

@@ -39,6 +39,25 @@ Deferred work. Context: Officer is collapsing from multi-tenant / open-source-re
         DB (`from:github OR from:deepgram` = 90+7 = 97 exactly).
   - [ ] **Remaining:** parenthesised grouping (nesting `(a OR b) c`), `in:sent/inbox/spam/trash`
         (folder scope), and relative dates (`newer_than:7d`). Grouping needs a recursive parser.
+  - [ ] **Group search results into threads too.** Folder views group by conversation (`ee11c94`), but
+        `/email/search` still returns one row per message. Apply the same `thread_id` collapse to the
+        FTS result set so search matches Gmail's grouped results.
+
+- [x] **Conversation threading** (done 2026-07-24, `ee11c94`). `thread_id` column on `emails`:
+      header-based for new mail (`id` = `sha1(Message-Id)`, so `References[0]` hashes to the root's
+      id — `computeThreadId` in `email-db.ts`), subject+counterpart backfill for already-synced mail.
+      `/messages` collapses to one row per thread (window fn) with count/unread; `/thread/:id` +
+      `/thread/:id/read`; reader renders a collapsible stack. Verified on synthetic + 18k real DB.
+  - [ ] **Upgrade old mail to exact threading.** One-time full re-fetch to capture `References` for
+        already-synced mail — replaces the subject+counterpart fallback (which can over-merge recurring
+        same-subject mail from one sender). Heavy/network-bound; opt-in.
+  - [ ] **Store the RFC `Message-Id` header** on ingest so replies can set a real `In-Reply-To`
+        (currently reply threading leans on subject/participants; `id` is a local hash, not the header).
+
+- [x] **Compose/reply/send** (done 2026-07-24). Gmail SMTP send with contacts autocomplete, rich
+      contenteditable body (inline images at the caret via paste/drag-drop, Bcc), single close button.
+- [x] **`busy_timeout` on the email db** (done 2026-07-24, `9527e0b`). API + email sidecar share
+      `emails.db`; wait out a concurrent writer instead of 500-ing with "database is locked".
 
 ## Known bugs