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/services/config.service.js

@@ -0,0 +1,17 @@
+import { getDb } from '../db/client.js'
+
+const sql = getDb()
+
+export const getAnonymityConfig = async () => {
+  const [row] = await sql`SELECT value FROM app_config WHERE key = 'anonymity'`
+  return { anonymity_enabled: row?.value?.enabled ?? true }
+}
+
+export const setAnonymityConfig = async (enabled) => {
+  await sql`
+    INSERT INTO app_config (key, value, updated_at)
+    VALUES ('anonymity', ${sql.json({ enabled })}, NOW())
+    ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value, updated_at = NOW()
+  `
+  return { anonymity_enabled: enabled }
+}