WebAuthn biometric + PWA widget + UI header fixes + mobile responsive

- WebAuthn: register/auth options, device management
- PWA widget page + manifest shortcuts
- Group schedule endpoint (timezones + locations)
- UI #3-#6: compact headers on tasks/calendar/projects/goals
- UI #9: mobile responsive top bars
- webauthn_credentials table

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/package.json

@@ -21,6 +21,7 @@
     "@fastify/swagger": "^9.7.0",
     "@fastify/swagger-ui": "^5.2.5",
     "@fastify/websocket": "^11.2.0",
+    "@simplewebauthn/server": "^12.0.0",
     "bcrypt": "^6.0.0",
     "bcryptjs": "^3.0.3",
     "dotenv": "^17.3.1",