chore(ui): removes dead utilities and op-log leftovers [#8260 - Tier A] (#8892)

* chore(ui): removes dead utilities and op-log leftovers [#8260 - Tier A]

* update readme and remove-unused-log-imports.ts

* restore benchmark test and make runnable

docs/sync-and-op-log/operation-log-architecture.md

@@ -2365,7 +2365,7 @@ src/app/op-log/
 │       ├── test-client.helper.ts             # Test client utilities
 │       └── operation-factory.helper.ts       # Test operation builders
 └── benchmarks/
-    └── operation-log-stress.spec.ts          # Performance stress tests
+    └── operation-log-stress.benchmark.ts     # Manual perf harness (not auto-run in CI)
 
 src/app/features/work-context/store/
 ├── work-context-meta.actions.ts          # Move actions (moveTaskInTodayList, etc.)

docs/sync-and-op-log/sqlite-migration-followup.md

@@ -138,7 +138,10 @@ captured on the next tick.
 - ⏳ **Remains: the on-device real-engine run.** sql.js validates the engine, not
   the Capacitor bridge or the native plugin's specific SQLite build/flags. The
   `operation-log-stress.benchmark.ts` harness is the lever for the on-device
-  perf + behavior pass (see B1 perf note).
+  perf + behavior pass (see B1 perf note). Run it explicitly with
+  `npm run test:file src/app/op-log/testing/benchmarks/operation-log-stress.benchmark.ts`;
+  it is compiled by `src/tsconfig.spec.json` but excluded from the auto-run
+  `**/*.spec.ts` set, so it never runs in normal CI.
 
 ### B3. Flip the DI token on native — init fix ✅ landed; token flip device-gated