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

@@ -215,7 +215,10 @@ func writeResponse(resp interface{}) {
 }
 
 func writeFramed(data []byte) {
-	fmt.Fprintf(os.Stdout, "Content-Length: %d\r\n\r\n%s", len(data), data)
+	// 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{}) {