feat(decoders): add the enablers for the sensor decoding layer

Groundwork for ADR-006. No decoding happens yet, but everything stage 2
needs is now in place:

* the demodulated bit string is carried in metadata["bits"] for MS, MU and
  MC messages. It was computed already but only its length was kept, and
  the FHEM decoding logic this layer mirrors works on bits, not on hex.
* SensorEvent holds the interpreted measurements, and DecodedMessage gains
  a single optional `sensor` field, so no existing signature changes. The
  MQTT serializer drops that field, keeping state/messages byte identical
  for current consumers.
* tools/fhem_testdata_import.py vendors the FHEM test vectors into
  tests/data/fhem/. They carry the raw telegram, the expected stage 1
  string and the expected stage 2 readings, which makes them the parity
  reference for both stages. Vendoring keeps the suite independent of a
  RFFHEM checkout sitting next to this one.

The new baseline test pins stage 1 at 86 of 99 reproduced vectors and
requires the five protocols with hardware behind them here (27, 50, 85,
125, 126) to match completely, so a stage 2 change cannot quietly damage
stage 1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KBqRw2DPXbSzhGBqB55cFZ

Author: sidey79

sd_protocols/manchester.py

@@ -135,6 +135,8 @@ def _demodulate_mc_data(self, name: str, protocol_id: int, clock: int, raw_hex:
 
         metadata = {
             "protocol_id": protocol_id,
+            "bits": bit_data,
+            "bit_length": len(bit_data),
             "rssi": None,
             "freq_afc": None,
         }

sd_protocols/message_synced.py

@@ -234,6 +234,7 @@ def demodulate_ms(self, msg_data: Dict[str, Any], msg_type: str = "MS") -> List[
                 "protocol_id": pid,
                 "payload": final_payload,
                 "meta": {
+                    "bits": bit_str,
                     "bit_length": len(bit_str),
                     "rssi": msg_data.get('R'),
                     "clock": clock_abs

sd_protocols/message_unsynced.py

@@ -283,6 +283,7 @@ def demodulate_mu(self, msg_data: Dict[str, Any], msg_type: str = "MU") -> List[
                     "protocol_id": pid,
                     "payload": final_payload,
                     "meta": {
+                        "bits": bit_str,
                         "bit_length": len(bit_str),
                         "rssi": msg_data.get('R'),
                         "clock": clock_abs

signalduino/mqtt.py

@@ -241,7 +241,10 @@ def _raw_frame_to_dict(raw_frame: RawFrame) -> dict:
 
         # Remove empty or non-useful fields for publication
         message_dict.pop("raw", None) # Do not publish raw frame data by default
-        
+        # Stage 2 results have their own topics (sensors/, rtl433/, fhem/), so this
+        # topic keeps the exact shape consumers already rely on. See ADR-006.
+        message_dict.pop("sensor", None)
+
         return json.dumps(message_dict, indent=4)
 
     async def publish_simple(self, subtopic: str, payload: str, retain: bool = False) -> None:

signalduino/types.py

@@ -21,6 +21,32 @@ class RawFrame:
     message_type: Optional[str] = None
 
 
+@dataclass(slots=True)
+class SensorEvent:
+    """Interpreted measurements of a single received frame (decoding stage 2).
+
+    While DecodedMessage carries the demodulated payload, this carries what the
+    payload means: temperature, humidity, battery state and so on. The keys used
+    in ``values`` are the FHEM reading names, because those are the de facto
+    standard across the ported protocols and keep the parity tests against the
+    FHEM test vectors a plain comparison. Output adapters map them to their own
+    naming.
+    """
+
+    protocol_id: str
+    model: str
+    sensor_type: str
+    device_id: str
+    sensor_id: str
+    values: dict[str, Any] = field(default_factory=dict)
+    units: dict[str, str] = field(default_factory=dict)
+    channel: Optional[int] = None
+    raw_hex: str = ""
+    dmsg: str = ""
+    rssi: Optional[float] = None
+    timestamp: datetime = field(default_factory=datetime.utcnow)
+
+
 @dataclass(slots=True)
 class DecodedMessage:
     """Higher-level frame after running through the parser."""
@@ -29,6 +55,7 @@ class DecodedMessage:
     payload: str
     raw: RawFrame
     metadata: dict = field(default_factory=dict)
+    sensor: Optional[SensorEvent] = None
 
 
 @dataclass(slots=True)