Record notifications-query-performance completion in backlog

By specifier.

specs/feature-backlog.md

@@ -31,30 +31,39 @@ focus is **front-end improvements** to `psf-memo-client` (the React SPA).
 
 ## In progress
 
-- **Notifications query performance (2026-09-18):** `GET /posts/notifications/:addr`
-  is slow because it full-scans the `likes`, `postChildren`, and `follows`
-  stores and loads a post for every candidate. The fix bounds the work to the
-  viewer's activity inside a configurable block window
-  (`NOTIFICATION_BLOCK_WINDOW`, default 25000; cutoff =
-  `status.chainBlockHeight - window`): the viewer's posts are read from
-  `addrPostHeights` within the window, likes and replies are prefix-scanned
-  from `postLikes`/`postChildren` per post, and follows are read from a new
-  followee-keyed, height-ordered `followeeHeights` index maintained by the
-  indexer. `pagination.total` counts only in-window notifications. Affected
-  components: `psf-memo-indexer` (index writes) and `psf-memo-db` (read path,
-  config). Specs:
-  `psf-memo-indexer/specs/followee-heights-indexing.feature`,
-  `psf-memo-db/specs/backfill-followee-index.feature`,
-  `psf-memo-db/specs/notifications-query-performance.feature`.
-  **Developer documentation:** update
-  `psf-memo-indexer/dev-docs/psf-memo-db.md` (new `followeeHeights` store,
-  `NOTIFICATION_BLOCK_WINDOW` config, read-route notes) and
-  `psf-memo-indexer/dev-docs/design-decisions-and-tradeoffs.md` (why per-object
-  scans plus a block window replace the full-store scans), and let the architect
-  record the per-task what/why summary under `docs/reviews/`.
+_(none)_
 
 ## Recently completed
 
+- **Notifications query performance (2026-09-18):** `GET /posts/notifications/:addr`
+  is now bounded to the viewer's activity inside a configurable block window
+  (`NOTIFICATION_BLOCK_WINDOW`, default 25000; cutoff
+  `status.chainBlockHeight - window`) instead of full-scanning `likes`,
+  `postChildren`, and `follows`. The viewer's posts are read from
+  `addrPostHeights` within the window, likes and replies are prefix-scanned
+  from `postLikes`/`postChildren` per post, and follows come from a new
+  followee-keyed, height-ordered `followeeHeights` index written by the indexer
+  (`/level/followeeheight` route, `backfill-followee-index` utility).
+  `pagination.total` counts only in-window notifications, and because a
+  notification is drawn from the viewer's content inside the window, an
+  interaction with a post older than the window is not returned even when the
+  interaction itself is recent. Indexer + DB. Specs:
+  `psf-memo-indexer/specs/followee-heights-indexing.feature`,
+  `psf-memo-db/specs/backfill-followee-index.feature`,
+  `psf-memo-db/specs/notifications-query-performance.feature`. Merged to
+  `master` at `a1eb548688` (review commit `c9728cc301`; records
+  `docs/reviews/notifications-query-performance-verification.json` (db) and
+  `docs/reviews/notifications-query-performance-indexer-verification.json`; the
+  later `a1eb548` commit is docs-only, so the records are valid for the merged
+  tree). Developer documentation captured in
+  `psf-memo-indexer/dev-docs/psf-memo-db.md` (new `followeeHeights` store,
+  `NOTIFICATION_BLOCK_WINDOW` config, route notes) and
+  `psf-memo-indexer/dev-docs/design-decisions-and-tradeoffs.md` (why per-object
+  scans plus a block window replace the full-store scans); architect summary
+  `docs/reviews/notifications-query-performance-summary.md`. Independent
+  acceptance check after merge: db notifications 10/10, db backfill 4/4,
+  indexer 4/4.
+
 - **Topics table layout (2026-09-18):** the topics page now renders topics in
   a react-bootstrap `Table`, so the four columns line up. A pure
   `buildTopicsTable` view model (`psf-memo-client/src/services/topics-table.js`)
@@ -344,14 +353,11 @@ Reference: https://memo.sv/protocol (Wayback snapshot 2025-12-15)
   small; handoffs are blocked on a dirty tree. See `docs/process-improvements.md`
   for the what/why, commits, and verification evidence.
 
-## Next up: Notifications query performance
+## Next up: TBD
 
-Specification complete and awaiting coder handoff. Make
-`GET /posts/notifications/:addr` bounded to the viewer's activity in a
-configurable block window instead of full-scanning `likes`, `postChildren`, and
-`follows`. See **In progress** above for the specs and the developer
-documentation deliverable. Current direction otherwise remains front-end
-improvements to `psf-memo-client`.
+Current direction is front-end improvements to `psf-memo-client` (UI/UX polish,
+accessibility, performance, responsiveness, state handling, error surfacing).
+Ask the user for the next feature.
 
 ## Notes for future cycles