feat(database): add database layer architecture (#410)

- Add @esengine/database-drivers for MongoDB/Redis connection management
- Add @esengine/database for Repository pattern with CRUD, pagination, soft delete
- Refactor @esengine/transaction MongoStorage to use shared connection
- Add comprehensive documentation in Chinese and English

.changeset/database-layer-architecture.md

@@ -0,0 +1,48 @@
+---
+"@esengine/database-drivers": minor
+"@esengine/database": minor
+"@esengine/transaction": minor
+---
+
+feat: add database layer architecture
+
+Added new database packages with layered architecture:
+
+**@esengine/database-drivers (Layer 1)**
+- MongoDB connection with pool management, auto-reconnect, events
+- Redis connection with auto-reconnect, key prefix
+- Type-safe `IMongoCollection<T>` interface decoupled from mongodb types
+- Service tokens for dependency injection (`MongoConnectionToken`, `RedisConnectionToken`)
+
+**@esengine/database (Layer 2)**
+- Generic `Repository<T>` with CRUD, pagination, soft delete
+- `UserRepository` with registration, authentication, role management
+- Password hashing utilities using scrypt
+- Query operators: `$eq`, `$ne`, `$gt`, `$gte`, `$lt`, `$lte`, `$in`, `$nin`, `$like`, `$regex`
+
+**@esengine/transaction**
+- Refactored `MongoStorage` to use shared connection from `@esengine/database-drivers`
+- Removed factory pattern in favor of shared connection (breaking change)
+- Simplified API: `createMongoStorage(connection, options?)`
+
+Example usage:
+```typescript
+import { createMongoConnection } from '@esengine/database-drivers'
+import { UserRepository } from '@esengine/database'
+import { createMongoStorage, TransactionManager } from '@esengine/transaction'
+
+// Create shared connection
+const mongo = createMongoConnection({
+    uri: 'mongodb://localhost:27017',
+    database: 'game'
+})
+await mongo.connect()
+
+// Use for database operations
+const userRepo = new UserRepository(mongo)
+await userRepo.register({ username: 'john', password: '123456' })
+
+// Use for transactions (same connection)
+const storage = createMongoStorage(mongo)
+const txManager = new TransactionManager({ storage })
+```