test(hooks): finalize mutation test improvements and release acceptance

- Raise use-swipe-gesture mutation score to 66.13% (target 65%+)
- Maintain use-reduced-motion mutation score at 76.32% (target 50%+)
- Fix use-reduced-motion.ts ESLint set-state-in-effect warning
- Add UJ-10 deep searcher journey (category browse → article read → content discovery)
- Add 40 new test files (analytics, detail, sections, ui, lib components)
- Update test-strategy-plan.md to v2.0 (sync test count to 1591)
- Sync README.md with final release metrics

Quality gates: TS 0 errors, ESLint 0 errors, 121 suites / 1591 tests passed

package.json

@@ -27,6 +27,9 @@
     "test:visual:browsers": "cd e2e && npx playwright test visual-regression.spec.ts --project=visual-chromium-desktop --project=visual-firefox-desktop --project=visual-webkit-desktop",
     "test:performance": "k6 run tests/performance/load-test.js",
     "test:stress": "k6 run tests/performance/stress-test.js",
+    "test:integration": "jest --testPathPatterns='src/app/api/'",
+    "test:performance:api": "k6 run tests/performance/api-test.js",
+    "test:performance:soak": "k6 run tests/performance/soak-test.js",
     "test:smoke": "cd e2e && npx playwright test --grep @smoke",
     "test:critical": "cd e2e && npx playwright test --grep @critical",
     "test:e2e:fast": "cd e2e && npx playwright test --grep '@smoke|@critical'",