feat(v1): edit detection sensitivity from the settings tab

Adds write_local_event_tuning and a sensitivity group (confirm window,
horizontal angle, require-rapid-drop, require-lower-body) that persists to
the untracked local config and applies next start. 79 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

v1/tests/test_config.py

@@ -129,6 +129,32 @@ def test_write_local_camera_source_round_trips_through_load_config(tmp_path):
     assert config.source_id == "hik"
 
 
+def test_write_local_event_tuning_round_trips_and_preserves_other_fields(tmp_path):
+    from v1.config import write_local_event_tuning
+
+    config_file = tmp_path / "config.local.json"
+    _write_config(
+        config_file,
+        {"id": "seed", "host": "192.0.2.10", "username": "u", "password": "p"},
+    )
+
+    write_local_event_tuning(
+        config_file,
+        require_rapid_drop=True,
+        require_lower_body=True,
+        horizontal_angle_threshold_degrees=35.0,
+        confirm_window_seconds=2.5,
+    )
+    config = load_config(config_file)
+
+    assert config.event.require_rapid_drop is True
+    assert config.event.require_lower_body is True
+    assert config.event.horizontal_angle_threshold_degrees == 35.0
+    assert config.event.confirm_window_seconds == 2.5
+    # unrelated event fields are preserved from the seed
+    assert config.event.cooldown_seconds == 10.0
+
+
 def test_public_example_config_has_no_embedded_credentials():
     from pathlib import Path