Add presence detection, person/vehicle AI detection, health monitoring

Task 1 — Presence: ping family phones, derive household state
(EMPTY/KIDS_HOME/ADULTS_HOME/ALL_HOME), configurable departure delay,
per-member roles, auto-arm actions via MQTT.

Task 2 — Detection: MobileNet-SSD v2 via OpenCV DNN for person/vehicle
classification. Vehicle color/size fingerprinting for known car matching.
Zone-based filtering per camera. Model download script.

Task 3 — Health: periodic disk/MQTT/subsystem checks, auto-prune oldest
non-starred recordings on disk pressure, daily digest builder.

126 tests passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/unit/test_presence.py

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+"""Tests for presence detection."""
+
+import time
+from unittest.mock import patch
+
+from vigilar.config import PresenceConfig, PresenceMember
+from vigilar.constants import HouseholdState
+from vigilar.presence.models import MemberPresence, derive_household_state
+
+
+class TestDeriveHouseholdState:
+    def test_empty_when_no_members_home(self):
+        members = [
+            MemberPresence(name="Dad", role="adult", is_home=False, last_seen=0),
+            MemberPresence(name="Mom", role="adult", is_home=False, last_seen=0),
+        ]
+        assert derive_household_state(members) == HouseholdState.EMPTY
+
+    def test_all_home(self):
+        members = [
+            MemberPresence(name="Dad", role="adult", is_home=True, last_seen=0),
+            MemberPresence(name="Mom", role="adult", is_home=True, last_seen=0),
+            MemberPresence(name="Kid", role="child", is_home=True, last_seen=0),
+        ]
+        assert derive_household_state(members) == HouseholdState.ALL_HOME
+
+    def test_kids_home_only(self):
+        members = [
+            MemberPresence(name="Dad", role="adult", is_home=False, last_seen=0),
+            MemberPresence(name="Kid", role="child", is_home=True, last_seen=0),
+        ]
+        assert derive_household_state(members) == HouseholdState.KIDS_HOME
+
+    def test_adults_home_not_all(self):
+        members = [
+            MemberPresence(name="Dad", role="adult", is_home=True, last_seen=0),
+            MemberPresence(name="Kid", role="child", is_home=False, last_seen=0),
+        ]
+        assert derive_household_state(members) == HouseholdState.ADULTS_HOME
+
+    def test_adults_home_no_children_configured(self):
+        members = [
+            MemberPresence(name="Dad", role="adult", is_home=True, last_seen=0),
+        ]
+        assert derive_household_state(members) == HouseholdState.ALL_HOME
+
+    def test_empty_list(self):
+        assert derive_household_state([]) == HouseholdState.EMPTY
+
+
+class TestPingHost:
+    @patch("vigilar.presence.monitor.subprocess.run")
+    def test_ping_success(self, mock_run):
+        from vigilar.presence.monitor import ping_host
+        mock_run.return_value = type("R", (), {"returncode": 0})()
+        assert ping_host("192.168.1.50") is True
+
+    @patch("vigilar.presence.monitor.subprocess.run")
+    def test_ping_failure(self, mock_run):
+        from vigilar.presence.monitor import ping_host
+        mock_run.return_value = type("R", (), {"returncode": 1})()
+        assert ping_host("192.168.1.50") is False
+
+    @patch("vigilar.presence.monitor.subprocess.run")
+    def test_ping_timeout(self, mock_run):
+        import subprocess as sp
+        from vigilar.presence.monitor import ping_host
+        mock_run.side_effect = sp.TimeoutExpired(cmd="ping", timeout=2)
+        assert ping_host("192.168.1.50") is False
+
+
+class TestDepartureDelay:
+    def test_not_departed_within_delay(self):
+        from vigilar.presence.monitor import should_mark_away
+        last_seen = time.monotonic() - 300  # 5 min ago
+        assert should_mark_away(last_seen, departure_delay_m=10) is False
+
+    def test_departed_after_delay(self):
+        from vigilar.presence.monitor import should_mark_away
+        last_seen = time.monotonic() - 700  # 11+ min ago
+        assert should_mark_away(last_seen, departure_delay_m=10) is True