Add Sentry source maps and release tracking

- @sentry/vite-plugin uploads source maps during Docker build
- Release tagged with git SHA (SENTRY_RELEASE) on both client and server
- Environment set to production/development for filtering
- CD passes SENTRY_AUTH_TOKEN + SENTRY_RELEASE as Docker build args
- docker-compose passes SENTRY_RELEASE to runtime containers

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

package.json

@@ -28,6 +28,7 @@
     "@react-router/dev": "^7.13.1",
     "@react-router/node": "^7.13.1",
     "@react-router/serve": "^7.13.1",
+    "@sentry/vite-plugin": "^5.1.1",
     "@tailwindcss/vite": "^4.2.2",
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.2",