Mock: add Thermostat + Button RequestProperties handlers

The HA coordinator walks ObjectType.THERMOSTAT (6) and ObjectType.BUTTON
(3) via raw RequestProperties to discover them — the high-level
get_object_properties() path only knows zones/units/areas in v1.0. The
mock was returning Nak for both, which made HA discover zero thermostats
and zero buttons no matter how MockState was seeded.

src/omni_pca/mock_panel.py:
- New MockButtonState dataclass (just a name)
- MockState gains buttons: dict[int, MockButtonState] (with the same
  bare-string -> dataclass __post_init__ promotion as the others)
- _OBJ_BUTTON = 3, _BUTTON_NAME_LEN = 12, _THERMOSTAT_NAME_LEN = 12
  constants
- thermostat_name_bytes() / button_name_bytes() helpers
- _build_thermostat_properties() emits the 23-byte Properties body
  matching ThermostatProperties.parse offsets (object number BE u16,
  communicating flag, current temp, heat/cool setpoints, system/fan/
  hold modes, thermostat type, 12-byte NUL-padded name)
- _build_button_properties() emits the 15-byte body (object number BE
  u16 + 12-byte name)
- _reply_properties / _object_store dispatch both new types

tests/test_e2e_client_mock.py — two new e2e tests drive raw
RequestProperties walks for thermostats and buttons against a seeded
mock and assert ThermostatProperties / ButtonProperties parse cleanly,
mirroring what the HA coordinator's _walk_properties() does.

333 tests pass (was 331); ruff clean. Mock surface now matches every
opcode the HA coordinator and entity platforms actually call.

src/omni_pca/mock_panel.py

@@ -59,6 +59,7 @@ _log = logging.getLogger(__name__)
 # enuObjectType (clsOmniLink2.cs / enuObjectType.cs)
 _OBJ_ZONE = 1
 _OBJ_UNIT = 2
+_OBJ_BUTTON = 3
 _OBJ_AREA = 5
 _OBJ_THERMOSTAT = 6
 
@@ -66,6 +67,8 @@ _OBJ_THERMOSTAT = 6
 _ZONE_NAME_LEN = 15
 _UNIT_NAME_LEN = 12
 _AREA_NAME_LEN = 12
+_BUTTON_NAME_LEN = 12
+_THERMOSTAT_NAME_LEN = 12
 _PHONE_LEN = 24
 
 # Per-object-type record sizes for the basic Status (opcode 35) reply.
@@ -156,6 +159,13 @@ class MockZoneState:
         return val & 0xFF
 
 
+@dataclass
+class MockButtonState:
+    """One programmable button macro (no live state — buttons just fire programs)."""
+
+    name: str = ""
+
+
 @dataclass
 class MockThermostatState:
     """One programmable thermostat. Defaults are sane Omni Pro II values."""
@@ -197,6 +207,7 @@ class MockState:
     units: dict[int, MockUnitState] = field(default_factory=dict)
     areas: dict[int, MockAreaState] = field(default_factory=dict)
     thermostats: dict[int, MockThermostatState] = field(default_factory=dict)
+    buttons: dict[int, MockButtonState] = field(default_factory=dict)
 
     # User-code table for ExecuteSecurityCommand validation.
     # Mapping is ``{code_index: 4-digit pin}``; the panel returns the
@@ -230,6 +241,7 @@ class MockState:
         self.units = _promote_dict(self.units, MockUnitState)
         self.areas = _promote_dict(self.areas, MockAreaState)
         self.thermostats = _promote_dict(self.thermostats, MockThermostatState)
+        self.buttons = _promote_dict(self.buttons, MockButtonState)
 
     # ---- name-bytes helpers (kept for back-compat with old callers) -----
 
@@ -245,6 +257,14 @@ class MockState:
         a = self.areas.get(idx)
         return _name_bytes(a.name if a else "", _AREA_NAME_LEN)
 
+    def thermostat_name_bytes(self, idx: int) -> bytes:
+        t = self.thermostats.get(idx)
+        return _name_bytes(t.name if t else "", _THERMOSTAT_NAME_LEN)
+
+    def button_name_bytes(self, idx: int) -> bytes:
+        b = self.buttons.get(idx)
+        return _name_bytes(b.name if b else "", _BUTTON_NAME_LEN)
+
 
 def _promote_dict(
     raw: dict[int, object],
@@ -618,6 +638,10 @@ class MockPanel:
             return self._build_unit_properties(target)
         if obj_type == _OBJ_AREA:
             return self._build_area_properties(target)
+        if obj_type == _OBJ_THERMOSTAT:
+            return self._build_thermostat_properties(target)
+        if obj_type == _OBJ_BUTTON:
+            return self._build_button_properties(target)
         return _build_nak(OmniLink2MessageType.RequestProperties)
 
     def _object_store(self, obj_type: int) -> dict[int, object] | None:
@@ -629,6 +653,8 @@ class MockPanel:
             return self.state.areas  # type: ignore[return-value]
         if obj_type == _OBJ_THERMOSTAT:
             return self.state.thermostats  # type: ignore[return-value]
+        if obj_type == _OBJ_BUTTON:
+            return self.state.buttons  # type: ignore[return-value]
         return None
 
     def _build_zone_properties(self, index: int) -> Message:
@@ -678,6 +704,58 @@ class MockPanel:
         )
         return encode_v2(OmniLink2MessageType.Properties, body)
 
+    def _build_thermostat_properties(self, index: int) -> Message:
+        # Properties.Data layout for Thermostat (Data[0]=opcode, body starts
+        # at Data[1]. ``payload`` here strips the opcode; payload[i]==Data[i+1]):
+        #   payload[0]    object type (Thermostat = 6)
+        #   payload[1..2] object number (BE u16)
+        #   payload[3]    communicating flag
+        #   payload[4]    temperature raw
+        #   payload[5]    heat setpoint raw
+        #   payload[6]    cool setpoint raw
+        #   payload[7]    mode
+        #   payload[8]    fan mode
+        #   payload[9]    hold mode
+        #   payload[10]   thermostat type
+        #   payload[11..22] 12-byte name
+        t = self.state.thermostats.get(index)
+        body = (
+            bytes(
+                [
+                    _OBJ_THERMOSTAT,
+                    (index >> 8) & 0xFF,
+                    index & 0xFF,
+                    t.status if t else 0,                    # communicating flag
+                    t.temperature_raw if t else 0,
+                    t.heat_setpoint_raw if t else 0,
+                    t.cool_setpoint_raw if t else 0,
+                    t.system_mode if t else 0,
+                    t.fan_mode if t else 0,
+                    t.hold_mode if t else 0,
+                    1,                                       # thermostat type: AUTO_HEAT_COOL
+                ]
+            )
+            + self.state.thermostat_name_bytes(index)
+        )
+        return encode_v2(OmniLink2MessageType.Properties, body)
+
+    def _build_button_properties(self, index: int) -> Message:
+        # Properties.Data layout for Button:
+        #   payload[0]      object type (Button = 3)
+        #   payload[1..2]   object number (BE u16)
+        #   payload[3..14]  12-byte name (NUL-padded)
+        body = (
+            bytes(
+                [
+                    _OBJ_BUTTON,
+                    (index >> 8) & 0xFF,
+                    index & 0xFF,
+                ]
+            )
+            + self.state.button_name_bytes(index)
+        )
+        return encode_v2(OmniLink2MessageType.Properties, body)
+
     def _build_area_properties(self, index: int) -> Message:
         # Properties.Data for Area:
         #   [0]=opcode, [1]=ObjectType, [2..3]=ObjectNumber,

tests/test_e2e_client_mock.py

@@ -18,6 +18,7 @@ from omni_pca.connection import HandshakeError
 from omni_pca.events import ArmingChanged, UnitStateChanged
 from omni_pca.mock_panel import (
     MockAreaState,
+    MockButtonState,
     MockPanel,
     MockState,
     MockThermostatState,
@@ -272,6 +273,76 @@ async def test_e2e_unit_command_pushes_unit_state_changed_event() -> None:
         assert ev.is_on is True
 
 
+async def test_e2e_thermostat_properties_discovery() -> None:
+    """The HA coordinator walks thermostats via raw RequestProperties; ensure
+    the mock answers and the response parses cleanly into ThermostatProperties.
+    """
+    from omni_pca.models import ObjectType as ObjType
+    from omni_pca.models import ThermostatProperties
+    from omni_pca.opcodes import OmniLink2MessageType
+
+    state = MockState(
+        thermostats={
+            1: MockThermostatState(name="LIVING_ROOM"),
+            3: MockThermostatState(name="MASTER"),
+        }
+    )
+    panel = MockPanel(controller_key=CONTROLLER_KEY, state=state)
+    async with (
+        panel.serve() as (host, port),
+        OmniClient(host=host, port=port, controller_key=CONTROLLER_KEY) as cli,
+    ):
+        found: dict[int, str] = {}
+        cursor = 0
+        for _ in range(10):
+            payload = bytes(
+                [int(ObjType.THERMOSTAT), (cursor >> 8) & 0xFF, cursor & 0xFF, 1, 0, 0, 0]
+            )
+            reply = await cli.connection.request(
+                OmniLink2MessageType.RequestProperties, payload
+            )
+            if reply.opcode == int(OmniLink2MessageType.EOD):
+                break
+            t = ThermostatProperties.parse(reply.payload)
+            found[t.index] = t.name
+            cursor = t.index
+    assert found == {1: "LIVING_ROOM", 3: "MASTER"}
+
+
+async def test_e2e_button_properties_discovery() -> None:
+    """Same idea for button discovery (the HA coordinator drives this too)."""
+    from omni_pca.models import ButtonProperties
+    from omni_pca.models import ObjectType as ObjType
+    from omni_pca.opcodes import OmniLink2MessageType
+
+    state = MockState(
+        buttons={
+            1: MockButtonState(name="GOOD_MORNING"),
+            5: MockButtonState(name="MOVIE_MODE"),
+        }
+    )
+    panel = MockPanel(controller_key=CONTROLLER_KEY, state=state)
+    async with (
+        panel.serve() as (host, port),
+        OmniClient(host=host, port=port, controller_key=CONTROLLER_KEY) as cli,
+    ):
+        found: dict[int, str] = {}
+        cursor = 0
+        for _ in range(10):
+            payload = bytes(
+                [int(ObjType.BUTTON), (cursor >> 8) & 0xFF, cursor & 0xFF, 1, 0, 0, 0]
+            )
+            reply = await cli.connection.request(
+                OmniLink2MessageType.RequestProperties, payload
+            )
+            if reply.opcode == int(OmniLink2MessageType.EOD):
+                break
+            b = ButtonProperties.parse(reply.payload)
+            found[b.index] = b.name
+            cursor = b.index
+    assert found == {1: "GOOD_MORNING", 5: "MOVIE_MODE"}
+
+
 async def test_e2e_acknowledge_alerts() -> None:
     panel = MockPanel(controller_key=CONTROLLER_KEY)
     async with (