fix(mcp-server): add graceful shutdown to prevent zombie processes (#477)

* fix(mcp-server): add graceful shutdown to prevent zombie processes

Add lifecycle handlers to properly exit the MCP server when the parent
application closes:

- Listen for stdin close/end events (primary method for all platforms)
- Handle SIGINT/SIGTERM signals
- Handle stdout broken pipe errors
- Export shutdown() function from http-server to clean up resources

* chore(mcp-server): bump version to 0.1.11

packages/mcp-server/src/index.ts

@@ -39,6 +39,7 @@ import {
     getState,
     requestSync,
     setState,
+    shutdown,
     startHttpServer,
     waitForSync,
 } from "./http-server.js"
@@ -618,6 +619,31 @@ server.registerTool(
     },
 )
 
+// Graceful shutdown handler
+let isShuttingDown = false
+function gracefulShutdown(reason: string) {
+    if (isShuttingDown) return
+    isShuttingDown = true
+    log.info(`Shutting down: ${reason}`)
+    shutdown()
+    process.exit(0)
+}
+
+// Handle stdin close (primary method - works on all platforms including Windows)
+process.stdin.on("close", () => gracefulShutdown("stdin closed"))
+process.stdin.on("end", () => gracefulShutdown("stdin ended"))
+
+// Handle signals (may not work reliably on Windows)
+process.on("SIGINT", () => gracefulShutdown("SIGINT"))
+process.on("SIGTERM", () => gracefulShutdown("SIGTERM"))
+
+// Handle broken pipe (writing to closed stdout)
+process.stdout.on("error", (err) => {
+    if (err.code === "EPIPE" || err.code === "ERR_STREAM_DESTROYED") {
+        gracefulShutdown("stdout error")
+    }
+})
+
 // Start the MCP server
 async function main() {
     log.info("Starting MCP server for Next AI Draw.io (embedded mode)...")