feat: initial XCClaw基础架构

- 基于 FastAPI 的 Web API 服务
- OpenCode API 客户端封装
- 会话管理器（同步/异步任务执行）
- APScheduler 定时任务调度
- 完整的 REST API 端点

app/main.py

@@ -0,0 +1,37 @@
+from contextlib import asynccontextmanager
+from fastapi import FastAPI
+from app.api.routes import router
+from app.services.scheduler import scheduler_service
+from app.services.opencode_client import opencode_client
+from app.core.config import settings
+from app.core.logging import logger
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    logger.info("Starting XCClaw server...")
+    scheduler_service.start()
+    yield
+    logger.info("Shutting down XCClaw server...")
+    scheduler_service.shutdown()
+    await opencode_client.close()
+
+
+app = FastAPI(
+    title="XCClaw",
+    description="基于 OpenCode Agent 的任务调度系统",
+    version="0.1.0",
+    lifespan=lifespan,
+)
+
+app.include_router(router)
+
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(
+        "app.main:app",
+        host=settings.app_host,
+        port=settings.app_port,
+        reload=True,
+    )