fix: remove redundant save_index call in server lifespan cleanup

- Fixes AttributeError during server shutdown where save_index() method was called on JSONIndexManager but doesn't exist
- In JSON-based indexing system, index is automatically saved during build_index() operations
- Update git workflow guidelines to allow direct commits with clean English messages
- Resolves issue #36 affecting langchain users

Author: johnhuang316

src/code_index_mcp/server.py

@@ -87,10 +87,6 @@ async def indexer_lifespan(_server: FastMCP) -> AsyncIterator[CodeIndexerContext
         if context.file_watcher_service:
             context.file_watcher_service.stop_monitoring()
 
-        # Only save index if project path has been set
-        if context.base_path and context.index_manager:
-            context.index_manager.save_index()
-
 # Create the MCP server with lifespan manager
 mcp = FastMCP("CodeIndexer", lifespan=indexer_lifespan, dependencies=["pathlib"])