fix(server): make the analyze worker's IPC send() failure-safe (#2264 review P3)

The worker's send() used `process.send?.(msg)` — the `?.` guards an undefined
channel but not a throw from an already-closed one (ERR_IPC_CHANNEL_CLOSED). A
throw in the catch-branch send() would escape the message handler and skip the
scheduled `setTimeout(process.exit(0))`, stranding the worker (with skip-close
leaving native handles open, #2264). Wrap process.send in try/catch so the exit
always fires; a vanished child is a failure to the parent regardless.

Not unit-tested: send() is module-private and importing the worker registers
process signal handlers; the change is a defensive try/catch around one call.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JBJomjoTdBV2eveDVq4JMm

gitnexus/src/server/analyze-worker.ts

@@ -44,7 +44,14 @@ export interface ErrorMessage {
 export type WorkerMessage = ProgressMessage | CompleteMessage | ErrorMessage;
 
 function send(msg: WorkerMessage) {
-  process.send?.(msg);
+  try {
+    process.send?.(msg);
+  } catch {
+    // The parent may have already disconnected the IPC channel
+    // (ERR_IPC_CHANNEL_CLOSED). Swallow so a failed notification can't escape the
+    // message/SIGTERM handlers and skip their scheduled process.exit (#2264 review
+    // P3) — a vanished child is treated as a failure by the parent regardless.
+  }
 }
 
 // Catch uncaught exceptions and unhandled rejections — report to parent