fix: wait for concurrent job to finish instead of returning permanent blocked error (FAR-61)

When multiple tasks are assigned simultaneously, only one K8s job can run
at a time (shared PVC/session guard). Previously, all other tasks received
k8s_concurrent_run_blocked immediately and stayed blocked forever.

Now the guard retries once: wait for all blocking jobs to complete via
waitForJobCompletion, then re-check before proceeding to create a new job.
If the re-check still shows a running job, the error is returned as before.

The agentCreationMutex already serializes guard-check + job-create, so
tasks naturally queue up and execute one at a time without concurrent jobs.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "paperclip-adapter-opencode-k8s",
-  "version": "0.1.22",
+  "version": "0.1.23",
   "description": "Paperclip adapter plugin that runs OpenCode agents as Kubernetes Jobs",
   "license": "MIT",
   "type": "module",