feat: integrate Sentry error tracking

- @sentry/nextjs installed and configured for client, server, and edge
- Instrumentation hook registers Sentry on Node.js and edge runtimes
- Global error boundary captures unhandled errors to Sentry
- next.config.ts wrapped with withSentryConfig (source maps disabled)
- No-op when NEXT_PUBLIC_SENTRY_DSN is not set

To enable: set NEXT_PUBLIC_SENTRY_DSN in .env.local or .env.production

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/package.json

@@ -19,6 +19,7 @@
     "@planarchy/shared": "workspace:*",
     "@planarchy/ui": "workspace:*",
     "@react-pdf/renderer": "^4.3.2",
+    "@sentry/nextjs": "^10.45.0",
     "@tanstack/react-query": "^5.62.16",
     "@tanstack/react-virtual": "^3.13.21",
     "@trpc/client": "^11.0.0",