feat(analytics): add Web Vitals tracking, GlitchTip user context, and funnel events

- Add web-vitals package with LCP/CLS/INP/FCP/TTFB → Umami tracking
- Set GlitchTip user context on login, clear on logout
- Add funnel events: first_content_created, user_return_visit,
  second_module_used, guest_converted
- Track first content via Dexie creating hook (fires once per user)
- Track module usage via route navigation effect
- Track guest→registered conversion on signup

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

packages/shared-utils/package.json

@@ -9,7 +9,8 @@
 		".": "./src/index.ts",
 		"./analytics": "./src/analytics.ts",
 		"./analytics-server": "./src/analytics-server.ts",
-		"./security-headers": "./src/security-headers.ts"
+		"./security-headers": "./src/security-headers.ts",
+		"./web-vitals": "./src/web-vitals.ts"
 	},
 	"scripts": {
 		"type-check": "tsc --noEmit",
@@ -17,7 +18,8 @@
 		"lint": "eslint ."
 	},
 	"dependencies": {
-		"date-fns": "^4.1.0"
+		"date-fns": "^4.1.0",
+		"web-vitals": "^5.2.0"
 	},
 	"devDependencies": {
 		"@types/node": "^24.10.1",