feat(server): in-memory async job store with thread-pool worker

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_jobs.py

@@ -0,0 +1,43 @@
+import time
+from server import jobs
+
+
+def _wait(job_id, status, timeout=2.0):
+    end = time.time() + timeout
+    while time.time() < end:
+        j = jobs.get_job(job_id)
+        if j and j.status == status:
+            return j
+        time.sleep(0.01)
+    raise AssertionError(f"job {job_id} never reached {status}")
+
+
+def test_create_job_is_queued():
+    job = jobs.create_job(hit={"artist": "A"}, message="queued msg")
+    assert job.status == "queued"
+    assert job.hit == {"artist": "A"}
+    assert jobs.get_job(job.id) is job
+
+
+def test_run_job_success_sets_done():
+    job = jobs.create_job(hit={}, message="m")
+    jobs.run_job(job.id, lambda: {"path": "/x", "lidarr_album_id": None},
+                 done_message="done!")
+    j = _wait(job.id, "done")
+    assert j.result == {"path": "/x", "lidarr_album_id": None}
+    assert j.message == "done!"
+    assert j.error is None
+
+
+def test_run_job_failure_sets_failed():
+    job = jobs.create_job(hit={}, message="m")
+    def boom():
+        raise RuntimeError("kaboom")
+    jobs.run_job(job.id, boom, done_message="done!", fail_message="it broke")
+    j = _wait(job.id, "failed")
+    assert j.error and "kaboom" in j.error
+    assert j.message == "it broke"
+
+
+def test_get_unknown_job_returns_none():
+    assert jobs.get_job("nope") is None