Session 217: NotificationCenter component — browser push preferences and alert feed

New component: NotificationCenter — centralized notification hub
aggregating alerts from emergency alerts, platform updates, and
sanctions tracker. 4 notification categories with filter buttons,
browser push permission management, service worker v3 integration,
per-category preference toggles with localStorage persistence,
search, expandable notification cards, copy-to-clipboard.
Privacy-first (no tracking). Integrated into Dashboard. 41 tests.

Co-authored-by: Stan2032 <68326386+Stan2032@users.noreply.github.com>

Author: Copilot

_agents/AGENT_HANDOFF.json

@@ -1,14 +1,14 @@
 {
   "handoff": {
-    "version": "14.5",
-    "date": "2026-03-06T16:00:00Z",
+    "version": "14.6",
+    "date": "2026-03-06T17:30:00Z",
     "repository": "Stan2032/global-anti-ccp-resistance-hub",
     "repository_path": "/home/runner/work/global-anti-ccp-resistance-hub/global-anti-ccp-resistance-hub",
-    "sessions_completed": 216,
+    "sessions_completed": 217,
     "state": "ACTIVE",
     "trust_level": "HIGH",
     "verification_rate": 0.99,
-    "supersedes": "AGENT_HANDOFF.json (v14.4, Session 215)",
+    "supersedes": "AGENT_HANDOFF.json (v14.5, Session 216)",
     "next_agent_prompt": "_agents/NEXT_AGENT_PROMPT.md"
   },
   "critical_reads": [
@@ -19,8 +19,8 @@
   ],
   "repository_metrics": {
     "total_files": "320+",
-    "frontend_tests": 3026,
-    "test_files": 172,
+    "frontend_tests": 3067,
+    "test_files": 173,
     "test_status": "ALL_PASSING",
     "build_time": "~5s",
     "profile_pages_built": 15,
@@ -29,7 +29,7 @@
     "sanctions_entries": 47,
     "sanctioned_officials": 34,
     "lazy_loaded_components": 81,
-    "sessions_completed": 216,    "eslint_status": "0_errors_0_warnings",
+    "sessions_completed": 217,    "eslint_status": "0_errors_0_warnings",
     "npm_vulnerabilities": 0,
     "codeql_alerts": 0,
     "mobile_responsiveness": "WCAG_2.5.5_44px_touch_targets_16px_base_font",
@@ -64,7 +64,7 @@
     "content_deduplication": "src_data_statistics_js_12_stats_central_source_of_truth",
     "client_side_encryption": "src_utils_encryption_js_RSA_OAEP_AES_256_GCM_for_PII",
     "backend_socket_cleanup": "socket_io_removed_3_files_deleted_session_118",
-    "components": 96
+    "components": 97
   },
   "session_131_changes": {
     "summary": "Test coverage for TaiwanDefenseStatus (4-tab defense analysis with military balance, allied support, scenarios), ChinaTechThreats (4-tab surveillance/infrastructure/data/response tracker), and CompanyTracker (filterable company database with JSON data, search, categories, expand/collapse). All three are complex data-heavy components.",

_agents/TODO.md

@@ -1,6 +1,6 @@
 # Global Anti-CCP Resistance Hub — Active To-Do List
 
-> Last Updated: March 6, 2026 (Session 216)
+> Last Updated: March 6, 2026 (Session 217)
 >
 > **Location:** `_agents/TODO.md` — Active tasks only.
 > **Completed tasks:** See `_agents/TODO_COMPLETED.md` for full archive.
@@ -239,7 +239,7 @@
 
 ### Technical Improvements
 - [x] **Offline Mode**: ✅ Service worker enhanced (Session 155): multi-strategy caching (cache-first for hashed assets, network-first for navigation, stale-while-revalidate for static files). Precaches app shell + icons. Offline page enhanced with cached page links. Bumped to v3.
-- [ ] **Push Notifications**: Alert users to breaking news and urgent actions
+- [x] **Push Notifications**: ✅ Phase 1 (Session 217): NotificationCenter component — centralized notification hub aggregating emergency alerts, platform updates, and sanctions data. 4 notification categories with filters, browser push permission management, service worker v3 integration, per-category preferences with localStorage persistence, search, expandable cards. Privacy-first (no server tracking). Phase 2: Server-side push via Web Push API.
 - [x] **Analytics Dashboard**: ✅ Phase 1 (Session 199): ContentAnalytics component — privacy-respecting content metrics dashboard aggregating insights from all 8 datasets. No user tracking. Integrated into Education Research tab. Phase 2: Server-side usage analytics (if needed).
 - [ ] **API Development**: Create public API for researchers to access data — ✅ Phase 1 (Session 197): Client-side `dataApi.js` module with structured access to all 8 datasets + search/filter/cross-dataset queries. ✅ Phase 1.5 (Session 200): Interactive API reference documentation (DataApiDocs component). Phase 2: REST API via Cloudflare Workers.
 - [ ] **Backup System**: Automated backups of all content