Fix CI hang: exit on termination signals and watchdog smoke test (#31)

The SIGINT/SIGTERM/SIGHUP handlers in runtime-diagnostics only logged the
signal name without calling process.exit. Registering a handler that does
not exit overrides Node's default termination behavior, so the server
ignored shutdown signals. The MCP SDK smoke test sends SIGTERM via
StdioClientTransport.close, so the child server stayed alive and the
"Run tests" job in the publish workflow hung until the workflow timeout.

Make the handlers log and then exit cleanly, and add a 60s hard timeout
to the smoke test so any future regression in shutdown can never hang
CI for hours.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: beautyfree

scripts/mcp-smoke-test.mjs

@@ -95,7 +95,21 @@ async function main() {
   }
 }
 
-main().catch((error) => {
-  console.error('MCP smoke test failed:', error);
-  process.exit(1);
-});
+// Hard timeout so a stuck child process can never hang CI for hours.
+const SMOKE_TEST_TIMEOUT_MS = 60_000;
+const watchdog = setTimeout(() => {
+  console.error(`MCP smoke test timed out after ${SMOKE_TEST_TIMEOUT_MS}ms`);
+  process.exit(2);
+}, SMOKE_TEST_TIMEOUT_MS);
+watchdog.unref();
+
+main()
+  .then(() => {
+    clearTimeout(watchdog);
+    process.exit(0);
+  })
+  .catch((error) => {
+    clearTimeout(watchdog);
+    console.error('MCP smoke test failed:', error);
+    process.exit(1);
+  });

src/runtime-diagnostics.ts

@@ -21,9 +21,14 @@ export function installRuntimeDiagnostics() {
     logInfo(`MCP Linear exit with code ${code}`);
   });
 
+  // Log the signal then exit. Without the explicit exit Node treats the
+  // registered handler as overriding default termination behavior, which
+  // makes the server ignore SIGTERM/SIGINT/SIGHUP and hang in CI when
+  // the smoke test or a parent process tries to shut it down.
   for (const signal of ['SIGINT', 'SIGTERM', 'SIGHUP'] as const) {
     process.on(signal, () => {
       logInfo(`MCP Linear received ${signal}`);
+      process.exit(0);
     });
   }
 }