fix: ensure abort fires even if shutdown throws in serve.ts

Wrap Instance.disposeAll() and server.stop() in try/finally so
abort.abort() always fires, preventing the process from hanging
if either call rejects.

packages/opencode/src/cli/cmd/serve.ts

@@ -18,9 +18,12 @@ export const ServeCommand = cmd({
     // kilocode_change start - graceful signal shutdown
     const abort = new AbortController()
     const shutdown = async () => {
-      await Instance.disposeAll()
-      await server.stop(true)
-      abort.abort()
+      try {
+        await Instance.disposeAll()
+        await server.stop(true)
+      } finally {
+        abort.abort()
+      }
     }
     process.on("SIGTERM", shutdown)
     process.on("SIGINT", shutdown)