feat(config): add MosaicConfig schema + loader with tier auto-detection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/gateway/src/database/database.module.ts

@@ -1,19 +1,21 @@
 import { Global, Inject, Module, type OnApplicationShutdown } from '@nestjs/common';
 import { createDb, type Db, type DbHandle } from '@mosaic/db';
 import { createStorageAdapter, type StorageAdapter } from '@mosaic/storage';
+import type { MosaicConfig } from '@mosaic/config';
+import { MOSAIC_CONFIG } from '../config/config.module.js';
 
 export const DB_HANDLE = 'DB_HANDLE';
 export const DB = 'DB';
 export const STORAGE_ADAPTER = 'STORAGE_ADAPTER';
 
-const DEFAULT_DATABASE_URL = 'postgresql://mosaic:mosaic@localhost:5432/mosaic';
-
 @Global()
 @Module({
   providers: [
     {
       provide: DB_HANDLE,
-      useFactory: (): DbHandle => createDb(),
+      useFactory: (config: MosaicConfig): DbHandle =>
+        createDb(config.storage.type === 'postgres' ? config.storage.url : undefined),
+      inject: [MOSAIC_CONFIG],
     },
     {
       provide: DB,
@@ -22,11 +24,8 @@ const DEFAULT_DATABASE_URL = 'postgresql://mosaic:mosaic@localhost:5432/mosaic';
     },
     {
       provide: STORAGE_ADAPTER,
-      useFactory: (): StorageAdapter =>
-        createStorageAdapter({
-          type: 'postgres',
-          url: process.env['DATABASE_URL'] ?? DEFAULT_DATABASE_URL,
-        }),
+      useFactory: (config: MosaicConfig): StorageAdapter => createStorageAdapter(config.storage),
+      inject: [MOSAIC_CONFIG],
     },
   ],
   exports: [DB, STORAGE_ADAPTER],