#Configuration

.env.local (untracked, see .env.example) supplies VITE_FIREBASE_*, an optional VITE_GOOGLE_PLACES_API_KEY, and VITE_USE_EMULATORS. No analytics.

Vite substitutes these at build time, so they are properties of a bundle rather than of a deployment: a build made without them cannot be repaired by supplying them afterwards. Absent, app.ts throws while the module graph is still evaluating, React never mounts, and the page is blank. A configResolved guard in vite.config.ts fails a production build that lacks the three app.ts requires, so that failure happens on the machine that can fix it; emulator builds (VITE_USE_EMULATORS=true) are exempt, since app.ts defaults them.

Hosting serves two sites. Target app serves dist/ with a predeploy hook that runs npm run build; target docs serves docs-dist/ with one that runs npm run docs:build. So firebase deploy builds what it ships, for both. Hooks are per target, so --only firestore:rules triggers neither, and --only hosting:app builds and ships the app alone.