Fix dryer detection when description pairs two model numbers (issue #79)

DVE50A8600V/A3 reports description
'DA_WM_TP1_21_COMMON_DVE50A8800_8600/DC92-02835A_0080' -- a paired
listing of two related model numbers (DVE50A8800 and DVE50A8600) joined
by an underscore, rather than the usual single trailing consumer-model
token. for_device_by_model only ever checked the literal last
underscore segment ('8600', which has no recognizable 2-letter prefix
on its own), so the real 'DV' token one segment earlier was never
reached and the device fell back to 'unknown' with only common
capabilities -- no dry level, cycle, or wrinkle-prevent entities.

Replace the single last-segment extraction with _consumer_model_key,
which scans segments from the end and returns the first one that
resolves. Behavior is unchanged for every existing single-token
description (the last segment still matches first); it just keeps
looking when that segment doesn't.

custom_components/localthings/registry/by_type/__init__.py

@@ -87,6 +87,26 @@ _CONSUMER_PREFIX_TO_KEY: dict[str, str] = {
 }
 
 
+def _consumer_model_key(description: str) -> Optional[str]:
+    """Registry key from the consumer-model token in `description`, or None.
+
+    Usually that token is the last '_'-delimited segment before any
+    '/board-info' suffix (e.g. '..._WW90DG6U25LEU4' -> 'WW90DG6U25LEU4').
+    But issue #79's dryer pairs two model numbers in one description --
+    '..._DVE50A8800_8600/DC92-...' -- so the true consumer token
+    ('DVE50A8800') sits one segment *before* the actual last segment
+    ('8600', a bare second model number with no recognizable prefix). Scan
+    segments from the end and take the first one that resolves, rather
+    than assuming the last segment is always it.
+    """
+    segments = (description or '').split('/', 1)[0].split('_')
+    for segment in reversed(segments):
+        key = _CONSUMER_PREFIX_TO_KEY.get(segment[:2].upper())
+        if key is not None:
+            return key
+    return None
+
+
 def for_device_by_model(model_num: str, description: str) -> Optional[DeviceRegistry]:
     """Fallback device-type detection for hardware that never reports
     oneUiVersion (confirmed for washers -- their /otninformation/vs/0 has
@@ -100,8 +120,7 @@ def for_device_by_model(model_num: str, description: str) -> Optional[DeviceRegi
         DeviceRegistry if the consumer-model code or modelNum resolves to a
         known type, None otherwise.
     """
-    token = (description or '').split('/', 1)[0].rsplit('_', 1)[-1]
-    key = _CONSUMER_PREFIX_TO_KEY.get(token[:2].upper())
+    key = _consumer_model_key(description)
     if key is None and '_REF_' in (model_num or ''):
         key = 'refrigerator'
     # Room air conditioners (e.g. ARTIK051_PRAC_20K) report no oneUiVersion and