Phase 2 refinements: Firebase config, dev environment fixes, phase 3 requirement draft

- Integrated Firebase SDK in both Flutter apps (google-services, firebase_options)
- Fixed auth flow, API client, and pairing/status blocs for dev environment
- Added full Flutter project scaffolds (android, ios, web, etc.)
- Added phase 3 chat engine requirement document
- Added bugreport zip pattern to gitignore

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

backend/src/routes/public/shared.config.routes.js

@@ -2,7 +2,7 @@ import { authenticate } from '../../plugins/auth.js'
 import { getAnonymityConfig } from '../../services/config.service.js'
 
 export const sharedConfigRoutes = async (app) => {
-  app.get('/anonymity', { preHandler: authenticate }, async (request, reply) => {
+  app.get('/anonymity', async (request, reply) => {
     const config = await getAnonymityConfig()
     return reply.send({ success: true, data: config })
   })