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

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

apps/gateway/src/memory/memory.module.ts

@@ -1,13 +1,29 @@
 import { Global, Module } from '@nestjs/common';
-import { createMemory, type Memory, createMemoryAdapter, type MemoryAdapter } from '@mosaic/memory';
+import {
+  createMemory,
+  type Memory,
+  createMemoryAdapter,
+  type MemoryAdapter,
+  type MemoryConfig,
+} from '@mosaic/memory';
 import type { Db } from '@mosaic/db';
-import { DB } from '../database/database.module.js';
+import type { StorageAdapter } from '@mosaic/storage';
+import type { MosaicConfig } from '@mosaic/config';
+import { MOSAIC_CONFIG } from '../config/config.module.js';
+import { DB, STORAGE_ADAPTER } from '../database/database.module.js';
 import { MEMORY } from './memory.tokens.js';
 import { MemoryController } from './memory.controller.js';
 import { EmbeddingService } from './embedding.service.js';
 
 export const MEMORY_ADAPTER = 'MEMORY_ADAPTER';
 
+function buildMemoryConfig(config: MosaicConfig, storageAdapter: StorageAdapter): MemoryConfig {
+  if (config.memory.type === 'keyword') {
+    return { type: 'keyword', storage: storageAdapter };
+  }
+  return { type: config.memory.type };
+}
+
 @Global()
 @Module({
   providers: [
@@ -18,7 +34,9 @@ export const MEMORY_ADAPTER = 'MEMORY_ADAPTER';
     },
     {
       provide: MEMORY_ADAPTER,
-      useFactory: (): MemoryAdapter => createMemoryAdapter({ type: 'pgvector' }),
+      useFactory: (config: MosaicConfig, storageAdapter: StorageAdapter): MemoryAdapter =>
+        createMemoryAdapter(buildMemoryConfig(config, storageAdapter)),
+      inject: [MOSAIC_CONFIG, STORAGE_ADAPTER],
     },
     EmbeddingService,
   ],