feat: introduce WeKnora Lite edition with lightweight configuration and deployment

- Added a new `.env.lite.example` file for the Lite version, providing a minimal configuration template.
- Updated `.env.example` to remove deprecated variables and include new Docreader settings.
- Enhanced Docker configurations to support the Lite version, including a new Dockerfile for the Docreader service.
- Introduced a Makefile target for building and running the Lite version, along with packaging capabilities.
- Created GitHub workflows for building and releasing Lite binaries, including Homebrew formula support.
- Implemented a new service file for managing the Lite version as a system service.

This update enables a streamlined, single-binary deployment of WeKnora, reducing external dependencies and simplifying setup.

.env.lite.example

@@ -0,0 +1,45 @@
+# WeKnora Lite 配置模板
+# 复制此文件为 .env.lite 并按需修改
+#   cp .env.lite.example .env.lite
+
+GIN_MODE=release
+
+# === 数据库 ===
+DB_DRIVER=sqlite
+DB_PATH=./data/weknora.db
+
+# === 检索引擎（FTS5 + sqlite-vec）===
+RETRIEVE_DRIVER=sqlite
+
+# === 文件存储 ===
+STORAGE_TYPE=local
+LOCAL_STORAGE_BASE_DIR=./data/files
+
+# === 流管理（内存，无 Redis）===
+STREAM_MANAGER_TYPE=memory
+
+# === LLM 服务 ===
+# Ollama 本地服务（默认地址，按需修改）
+OLLAMA_BASE_URL=http://127.0.0.1:11434
+# 如使用其他 OpenAI 兼容服务，取消注释：
+# OPENAI_API_KEY=sk-xxx
+# OPENAI_BASE_URL=https://api.openai.com/v1
+
+# === 安全配置（生产环境请务必修改！）===
+TENANT_AES_KEY=CHANGE-ME-32-char-secret-key!!!!
+JWT_SECRET=CHANGE-ME-jwt-secret
+
+# === 功能开关 ===
+NEO4J_ENABLE=false
+WEKNORA_SANDBOX_MODE=disabled
+ENABLE_GRAPH_RAG=false
+DISABLE_REGISTRATION=false
+
+# === 性能 ===
+CONCURRENCY_POOL_SIZE=3
+
+# Docreader 地址
+DOCREADER_ADDR=127.0.0.1:50051
+
+# Docreader 传输方式
+DOCREADER_TRANSPORT=grpc