refactor(db): consolidate ~20+ databases into 2 (mana_platform + mana_sync)

Mirrors the frontend unification (single IndexedDB) on the backend.
All services now use pgSchema() for isolation within one shared database,
enabling cross-schema JOINs, simplified ops, and zero DB setup for new apps.

- Migrate 7 services from pgTable() to pgSchema(): mana-user (usr),
  mana-media (media), todo, traces, presi, uload, cards
- Update all DATABASE_URLs in .env.development, docker-compose, configs
- Rewrite init-db scripts for 2 databases + 12 schemas
- Rewrite setup-databases.sh for consolidated architecture
- Update shared-drizzle-config default to mana_platform
- Update CLAUDE.md with new database architecture docs

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

services/mana-auth/src/config.ts

@@ -22,7 +22,10 @@ export function loadConfig(): Config {
 	const env = (key: string, fallback?: string) => process.env[key] || fallback || '';
 	return {
 		port: parseInt(env('PORT', '3001'), 10),
-		databaseUrl: env('DATABASE_URL', 'postgresql://manacore:devpassword@localhost:5432/mana_auth'),
+		databaseUrl: env(
+			'DATABASE_URL',
+			'postgresql://manacore:devpassword@localhost:5432/mana_platform'
+		),
 		syncDatabaseUrl: env(
 			'SYNC_DATABASE_URL',
 			'postgresql://manacore:devpassword@localhost:5432/mana_sync'