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>

packages/shared-hono/src/db.ts

@@ -36,7 +36,7 @@ export function createDb<TSchema extends Record<string, unknown>>(
 	const url =
 		opts?.url ??
 		process.env.DATABASE_URL ??
-		'postgresql://manacore:devpassword@localhost:5432/mana';
+		'postgresql://manacore:devpassword@localhost:5432/mana_platform';
 
 	const connection = postgres(url, {
 		max: opts?.maxConnections ?? 5,