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/cards-database/src/schema/aiGenerations.ts

@@ -1,6 +1,7 @@
-import { pgTable, uuid, text, varchar, timestamp, jsonb, index, pgEnum } from 'drizzle-orm/pg-core';
+import { uuid, text, varchar, timestamp, jsonb, index, pgEnum } from 'drizzle-orm/pg-core';
 import { relations } from 'drizzle-orm';
-import { decks } from './decks.js';
+import { cardsSchema } from './schema';
+import { decks } from './decks';
 
 // AI generation status enum
 export const aiGenerationStatusEnum = pgEnum('ai_generation_status', [
@@ -21,7 +22,7 @@ export interface AIGenerationMetadata {
 	[key: string]: unknown;
 }
 
-export const aiGenerations = pgTable(
+export const aiGenerations = cardsSchema.table(
 	'ai_generations',
 	{
 		id: uuid('id').primaryKey().defaultRandom(),