Phase 1 scaffold: auth for all apps

- Backend: Fastify with two listeners (public + internal), routes, services, DB migration + seed
- client_app: Flutter with BLoC, all auth screens (welcome, display name, register, OTP, force-register)
- mitra_app: Flutter with BLoC, OTP-only login
- control_center: React + Vite, email/password login, mitra/user management, anonymity settings
- Docs: phase1 plan, API contract, client app mockup
- CLAUDE.md and shared memory for all subprojects

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

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

@@ -0,0 +1,9 @@
+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) => {
+    const config = await getAnonymityConfig()
+    return reply.send({ success: true, data: config })
+  })
+}