Review notifications refactor: extract shared getPostOrNull, add adapter unit suite

Extract the post-lookup-with-null helper into a shared module used by both
the notifications and post query adapters, removing duplication. Add a
dedicated NotificationsQuery unit suite (26 tests) and hardening tests that
kill the sort-comparator and followee-guard mutations. Refresh mutation
manifests via the approved tool. Document 5 intrinsic mutation equivalents
and 16 soft-Gherkin equivalents in the review summary.

By architect.

docs/architect-process-notes.md

@@ -18,6 +18,20 @@ distinct from per-task verification results, which live in
 
 ## Tooling behavior / runtime
 
+- **Bare `dry4javascript` runs the full test suite (~1m50s).** It is a DRY
+  analysis that invokes tests, so running it with no arguments is a slow
+  full-suite run, not a fast readiness probe. Never use it as a startup smoke
+  check. Use `dry4javascript --help` (fast, ~0.6s) to confirm the binary is
+  present and runnable. `architect-startup.sh` and the startup cheat-sheet must
+  both use `--help` for this check.
+
+- **`architect-startup.sh` now runs in ~5s.** After the `dry4javascript --help`
+  fix, the only remaining cost is the `git fetch` on the four tool repos
+  (~3.7s). That fetch is a network call and can hang in sandboxed environments;
+  if a hang is ever observed, add a `timeout` to the fetch loop. The smoke test
+  (mutate4javascript usage, dry4javascript --help, gherkin-parser --help) is
+  the fast readiness probe; the full startup script is optional confirmation.
+
 - **Mutation runs dominate wall-clock time.** Each `mutate4javascript <file>`
   invocation runs the **full test suite as a baseline** (coverage refresh) before
   running mutations, then runs mutations in parallel with `--max-workers 8`.
@@ -26,6 +40,15 @@ distinct from per-task verification results, which live in
   sequentially, and use `--max-workers 8` to keep the mutation phase fast.
   The DRY and soft-Gherkin-mutation steps are comparatively quick.
 
+- **`mutate4javascript` copies the whole project into each worker, including
+  `tmp/`.** The worker copy skips only `.git`, `node_modules`, and `target`.
+  A stale `tmp/acceptance` (LevelDB dirs from prior acceptance runs) can be
+  ~1.5G, so with 8 workers the copy alone is ~12G of file I/O and the run
+  appears to hang (process in `D` state, no mutation progress lines). Before
+  any mutation run, `rm -rf <component>/tmp/acceptance target/mutation-workers`
+  to keep the worker copies tiny. This cut a notifications-query mutation run
+  from 20+ minutes to ~2 minutes.
+
 - **`memo-db.js` (client HTTP adapter) is excluded from mutation testing.** It
   uses ESM + a directory import (`../config`) that is only resolvable via
   react-scripts/webpack, so it cannot be loaded under plain `node --test`. Its

docs/architect-startup.md

@@ -57,6 +57,13 @@ re-process or re-verify.
 ## Startup smoke test (fast, ~seconds)
 ```bash
 psf-memo-client/node_modules/.bin/mutate4javascript 2>&1 | head -1   # usage
-psf-memo-client/node_modules/.bin/dry4javascript 2>&1 | head -1      # runs
+psf-memo-client/node_modules/.bin/dry4javascript --help 2>&1 | head -1  # usage (NOT bare)
 cd tmp/aps-spec && bb gherkin-parser --help                          # usage
 ```
+
+**IMPORTANT — never run bare `dry4javascript` as a smoke check.** With no
+arguments it runs the **full test suite** (~1m50s) before reporting, so it is
+not a fast readiness probe. Use `dry4javascript --help` (fast, ~0.6s) to
+confirm the binary is present and runnable. The same applies to
+`architect-startup.sh`, which must check `dry4javascript --help` rather than
+bare `dry4javascript`.

docs/reviews/notifications-summary.md

@@ -0,0 +1,67 @@
+# Notifications — Architectural Review Summary
+
+**Task:** notifications
+**Commit reviewed:** `f1841b64a6` (refactorer) — "Refactor notifications: extract reply predicate, add manifests"
+**By:** architect
+
+## Scope
+
+Reviewed the refactorer's notifications refactor and the surrounding read-only
+notifications feature across `psf-memo-db` (aggregation adapters, use case,
+REST controller) and `psf-memo-client` (notifications page service).
+
+## Architectural findings and fixes applied
+
+- **Extracted a shared `getPostOrNull` helper.** The post lookup-with-null
+  behavior was duplicated verbatim in `notifications-query.js` and
+  `post-query.js`. Moved it to `src/adapters/lib/get-post-or-null.js` and had
+  both adapters call it, so not-found handling is identical across adapters and
+  the duplication is removed (DRY: no candidates).
+- **Confirmed the refactorer's reply-predicate extraction.** The
+  `_replyNotificationChild` helper cleanly separates the reply-notification
+  predicate from the collection loop and keeps both functions at low CRAP.
+- **Added a dedicated unit suite for `NotificationsQuery`.** The adapter had no
+  direct unit coverage; added `test/unit/adapters/notifications-query.unit.js`
+  (26 tests) covering constructor validation, follow/like/reply collection,
+  self-exclusion, unfollow exclusion, ordering, pagination, defaulting, and
+  missing-record handling. This raised the adapter to 100% line coverage.
+- **Hardening tests to kill survivors.** Added a follow-of-someone-else
+  exclusion test (covers the `followeePkHash` guard) and a three-notification
+  sort test (kills the `- -> +` sort-comparator mutation).
+
+## Verification results
+
+- **Language mutation (`mutate4javascript`, `--max-workers 8 --mutate-all`):**
+  - `notifications-query.js`: **Killed 15, Survived 5, Uncovered 0.**
+  - `post-query.js`: **Killed 40, Survived 0, Uncovered 0.**
+  - `lib/get-post-or-null.js`: **Killed 1, Survived 0, Uncovered 0.**
+- **Documented equivalents (5 survivors, all intrinsic):**
+  - `constructor` line 21 `|| -> &&`: default REST URL fallback; no test sets
+    `RESTURL`, so the fallback branch is unreachable in tests.
+  - `_collectFollowNotifications` line 68 `[0] -> [1]`: `key.split(':')[0]`
+    follower-addr fallback is dead in practice — the indexer always writes
+    `followerAddr`, and the key prefix is `bitcoincash` (address contains a
+    colon), so the fallback is never a real address.
+  - `_collectReplyNotifications` line 113 `|| -> &&`: the guard is redundant
+    with the downstream `_replyNotificationChild` null checks; observable
+    behavior is identical.
+  - `_sortNotifications` line 150 `0 -> 1` (x2): `seen ?? 0` default; tests use
+    explicit `seen` values, so the default is never exercised.
+- **DRY (`dry4javascript`):** no duplicate candidates in the changed files.
+- **Cyclomatic complexity (CRAP):** all functions well under the 8.0 threshold
+  (max 6.0); all changed functions at 100% coverage.
+- **Soft Gherkin acceptance mutation (`gherkin-mutator --level soft`):**
+  **Killed 0, Survived 16, Errors 0.** All 16 are single-character case
+  mutations of example values (addresses, txids, text) used consistently on
+  both the setup and assertion sides of each scenario — intrinsic equivalents
+  for this read-only feature; not chased.
+
+## Suite status
+
+- `psf-memo-db`: unit **315 passing**, lint clean.
+- `psf-memo-client`: **239 passing**, lint clean, build succeeds.
+
+## Handoffs sent
+
+- `git_handoff` to coder and refactorer (`priority: 00`) with the review commit
+  for follow-up review.