feat: MQTT client with reconnection, topic matching, and callback dispatch

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

tests/test_mqtt_client.py

@@ -0,0 +1,48 @@
+import pytest
+from mqtt_home.mqtt_client import MqttClient
+from mqtt_home.config import Settings
+
+
+@pytest.fixture
+def mqtt_client():
+    settings = Settings(
+        mqtt_host="localhost",
+        mqtt_port=1883,
+        emqx_api_url="http://localhost:18083/api/v5",
+        emqx_api_key="test-key",
+        emqx_api_secret="test-secret",
+        database_url="sqlite+aiosqlite:///:memory:",
+    )
+    return MqttClient(settings)
+
+
+def test_topic_matches_exact():
+    assert MqttClient._topic_matches("home/light", "home/light") is True
+    assert MqttClient._topic_matches("home/light", "home/switch") is False
+
+
+def test_topic_matches_single_level_wildcard():
+    assert MqttClient._topic_matches("home/light/status", "home/+/status") is True
+    assert MqttClient._topic_matches("home/switch/status", "home/+/status") is True
+    assert MqttClient._topic_matches("home/light", "home/+") is True
+    assert MqttClient._topic_matches("home/light/extra", "home/+") is False
+
+
+def test_topic_matches_multi_level_wildcard():
+    assert MqttClient._topic_matches("homeassistant/light/abc/config", "homeassistant/#") is True
+    assert MqttClient._topic_matches("homeassistant/light/abc/config", "homeassistant/light/#") is True
+    assert MqttClient._topic_matches("other/topic", "homeassistant/#") is False
+
+
+def test_register_callback(mqtt_client):
+    async def cb(topic, payload):
+        pass
+
+    mqtt_client.on_message("home/#", cb)
+    assert "home/#" in mqtt_client._callbacks
+    assert len(mqtt_client._callbacks["home/#"]) == 1
+
+
+def test_initial_state(mqtt_client):
+    assert mqtt_client.is_connected is False
+    assert len(mqtt_client._client_id) > 0