feat: initialize cold display guard

tests/test_cli.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+import io
+import json
+import tempfile
+import unittest
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+from cold_display_guard.cli import run_jsonl
+from cold_display_guard.models import EngineSettings
+
+
+class CliTests(unittest.TestCase):
+    def test_processes_jsonl_observations(self) -> None:
+        settings = EngineSettings(
+            max_dwell_seconds=10,
+            trash_confirmation_seconds=5,
+            zone_ids=("r1c1",),
+        )
+        t0 = datetime(2026, 4, 27, 10, 0, tzinfo=timezone.utc)
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            input_path = Path(tmpdir) / "obs.jsonl"
+            input_path.write_text(
+                "\n".join(
+                    [
+                        json.dumps({"ts": t0.isoformat(), "zone_counts": {"r1c1": 1}}),
+                        json.dumps(
+                            {
+                                "ts": (t0 + timedelta(seconds=11)).isoformat(),
+                                "zone_counts": {"r1c1": 0},
+                            }
+                        ),
+                        json.dumps(
+                            {
+                                "ts": (t0 + timedelta(seconds=12)).isoformat(),
+                                "zone_counts": {"r1c1": 0},
+                                "trash_deposit": True,
+                            }
+                        ),
+                    ]
+                ),
+                encoding="utf-8",
+            )
+
+            output = io.StringIO()
+            exit_code = run_jsonl(input_path, settings, output)
+
+        self.assertEqual(exit_code, 0)
+        events = [json.loads(line) for line in output.getvalue().splitlines()]
+        self.assertEqual(
+            [event["event"] for event in events],
+            ["batch_started", "batch_pending_disposal", "batch_discarded"],
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()