fix(mcp): use NDJSON instead of LSP framing for MCP stdio

Replace Content-Length framing with newline-delimited JSON (NDJSON) for MCP stdio transport. MCP clients like Claude Code expect one JSON object per line, not LSP-style Content-Length headers. The previous framing caused clients to reject responses.

main.go

@@ -110,8 +110,8 @@ func main() {
 
 		debugLog("Response: %s", string(response))
 
-		// Write response to stdout
+		// Write response to stdout with Content-Length framing
-		fmt.Println(string(response))
+		writeFramed(response)
 	}
 }
 
@@ -211,7 +211,14 @@ func readMessage(reader *bufio.Reader) ([]byte, error) {
 
 func writeResponse(resp interface{}) {
 	data, _ := json.Marshal(resp)
-	fmt.Println(string(data))
+	writeFramed(data)
+}
+
+func writeFramed(data []byte) {
+	// MCP stdio transport uses newline-delimited JSON (NDJSON), not LSP-style
+	// Content-Length framing. Claude Code and other MCP clients reject
+	// Content-Length headers on stdio, so we emit one JSON object per line.
+	fmt.Fprintf(os.Stdout, "%s\n", data)
 }
 
 func debugLog(format string, args ...interface{}) {