feat: implement QuestionBank CRUD with pagination and template query

- Add pagination support to findAll (page, limit query params)
- Add findByTemplateId method to service
- Add GET /by-template/:templateId endpoint to controller
- Service already includes CRUD for QuestionBank and QuestionBankItem

server/README.md

@@ -0,0 +1,113 @@
+# Simple Knowledge Base - Backend Service (Server)
+
+A RAG (Retrieval-Augmented Generation) knowledge base backend system built with the [NestJS](https://nestjs.com/) framework. Provides file parsing, vector indexing, hybrid search, and multi-model management features.
+
+## 🌟 Key Features
+
+- **Intelligent Document Processing**: Integrated with [Apache Tika](https://tika.apache.org/) to support text extraction from various formats including PDF, Word, Markdown, and TXT.
+- **Efficient Vector Search**: Uses [Elasticsearch](https://www.elastic.co/) as the vector database. Supports hybrid search combining KNN vector search and full-text search.
+- **Flexible RAG Engine**: Built on LangChain. Supports customization of chunking rules and reranking.
+- **Multi-Model Provider**: Supports dynamic connection to OpenAI, Google Gemini, and locally deployed LLM models.
+- **Secure Management**: Built-in JWT authentication and user permission management.
+
+## 🛠️ Tech Stack
+
+- **Framework**: NestJS (TypeScript)
+- **Database**: SQLite (TypeORM)
+- **Search Engine**: Elasticsearch 8.x/9.x
+- **AI Framework**: LangChain
+- **Libraries**: RxJS, Class-Validator
+
+## 📋 Prerequisites
+
+Before running the project, ensure you have the following environment set up:
+
+- [Node.js](https://nodejs.org/) (v18 or higher recommended)
+- [Yarn](https://yarnpkg.com/)
+- [Docker](https://www.docker.com/) & Docker Compose (for infrastructure)
+
+## 🚀 Quick Start
+
+### 1. Start Infrastructure
+
+Use the `docker-compose.yml` file in the project root (`simple-kb/`) to quickly start Elasticsearch and Tika.
+
+```bash
+# Run from project root directory
+docker-compose up -d
+```
+
+After successful startup:
+
+- **Elasticsearch**: Listens on port `19200` (maps container's 9200 port)
+- **Tika**: Listens on port `9998`
+
+### 2. Install Dependencies
+
+Navigate to the `server` directory and install packages:
+
+```bash
+cd server
+yarn install
+```
+
+### 3. Environment Configuration
+
+The project uses environment variables for configuration. Make sure the settings are correct (especially Elasticsearch address):
+
+```env
+# Database path
+DATABASE_PATH=server/data/metadata.db
+
+# JWT secret
+JWT_SECRET=your_secure_secret
+
+# Elasticsearch settings (match docker-compose ports)
+ELASTICSEARCH_HOST=http://localhost:19200
+ELASTICSEARCH_INDEX=knowledge_base
+
+# Tika settings
+TIKA_HOST=http://localhost:9998
+
+# File upload storage path
+UPLOAD_FILE_PATH=./uploads
+```
+
+### 4. Start Services
+
+```bash
+# Development mode (recommended, with hot reload)
+yarn run start:dev
+
+# Build and run in production mode
+yarn build
+yarn run start:prod
+```
+
+The backend service runs on **http://localhost:13000** by default, with API prefix `/api`.
+
+## 🧪 Testing
+
+```bash
+# Unit tests
+yarn run test
+
+# E2E tests
+yarn run test:e2e
+```
+
+## ⚠️ Notes and Tips
+
+1. **Database Initialization**:
+   - On first run, TypeORM automatically creates `metadata.db` (or configured DB) under the `server/data/` directory.
+   - In development mode, with `synchronize: true`, table structures are auto-synced.
+
+2. **Elasticsearch Connection**:
+   - If you encounter a `Connection refused` error, check if Docker containers are running properly (`docker ps`).
+   - On service startup, an index named `knowledge_base` is automatically detected and created.
+
+3. **Default Account**:
+   - If you reset the database, either register a new user or refer to existing admin data. It's recommended to use the frontend registration feature to create the first user.
+
+4. **File Parsing**:
+   - When uploading large files, parsing by Tika may take a few seconds. Please wait while checking the frontend processing status.