feat: release 2.2.0 with PC-only tests and execution reliability fixes

Unify task scheduling and queue state, fix Android input and observation recovery, preserve screenshot paths, and match final review criteria accurately. Add collapsible copyable results and publish the complete 2.1.0 upgrade notes. Validation: 3189 backend tests, 326 frontend tests, 24 client tests, production build and quality gates.

tests/unit/runtime/test_trace_store.py

@@ -89,6 +89,32 @@ def test_update_trace_status_normalizes_success_alias(temp_trace_env):
     assert persisted["status"] == "completed"
 
 
+def test_conditional_status_update_checks_state_after_acquiring_lock(temp_trace_env, monkeypatch):
+    from contextlib import contextmanager
+
+    trace_store.init_trace("late-worker", "Test task", "Pro")
+    trace_store.update_trace_status("late-worker", "pending")
+    lock = trace_store._status_lock
+    terminal = {}
+
+    @contextmanager
+    def cancelled_before_lock(path):
+        with lock(path):
+            data = trace_store.read_status("late-worker")
+            data.update(status="cancelled", result="user stopped", end_time=123)
+            trace_store.write_status("late-worker", data)
+            terminal.update(data)
+            yield
+
+    monkeypatch.setattr(trace_store, "_status_lock", cancelled_before_lock)
+    result = trace_store.update_trace_status(
+        "late-worker", "running", expected_status="pending", result="must not overwrite"
+    )
+
+    assert result == terminal
+    assert trace_store.read_status("late-worker") == terminal
+
+
 def test_read_nonexistent_status(temp_trace_env):
     non_existent = str(uuid.uuid4())
     assert trace_store.read_status(non_existent) is None