feat: detect FlexWash (WV) washers; add combo dry-level select

- WV consumer-model prefix (FlexWash twin washers, e.g. WV55M9600AW)
  wasn't in the by-model fallback map, so these units fell through to
  the unknown-device registry with zero capabilities bound (#19).
- Washer/dryer combo units carry a writable dryLevel field directly on
  /washer/vs/0 with no separate dryer resource; add a self-gating
  select for it, off supportedDryLevel presence, so plain washers are
  unaffected (#22).

custom_components/localthings/registry/by_type/__init__.py

@@ -69,6 +69,7 @@ _CONSUMER_PREFIX_TO_KEY: dict[str, str] = {
     'WW': 'washer',
     'WD': 'washer',
     'WF': 'washer',
+    'WV': 'washer',  # FlexWash twin units (e.g. WV55M9600AW) -- issue #19
     'DV': 'dryer',
     'DW': 'dishwasher',
 }

custom_components/localthings/registry/capabilities/washer.py

@@ -82,6 +82,19 @@ WASHER_SETTINGS = Capability(
                    options_field='x.com.samsung.da.supportedRinseCycles',
                    write_fn=lambda p, rep, href=None: (
                        ['washer', 'vs', '0'], {'x.com.samsung.da.rinseCycles': p})),
+        # Washer/dryer combo units carry a dryLevel field on the wash
+        # resource itself (no separate dryer device/course) -- see issue
+        # #22. Self-gates off on plain washers, which never report
+        # supportedDryLevel.
+        SelectDesc(key='dry_level', field='x.com.samsung.da.dryLevel',
+                   name='Dry level', icon='mdi:tumble-dryer',
+                   entity_category='config',
+                   translation_key='washer_dry_level',
+                   options_field='x.com.samsung.da.supportedDryLevel',
+                   exists_fn=lambda rep, resources: bool(
+                       rep.get('x.com.samsung.da.supportedDryLevel')),
+                   write_fn=lambda p, rep, href=None: (
+                       ['washer', 'vs', '0'], {'x.com.samsung.da.dryLevel': p})),
     ),
 )
 

custom_components/localthings/strings.json

@@ -119,6 +119,18 @@
           "02": "2x",
           "03": "3x"
         }
+      },
+      "washer_dry_level": {
+        "state": {
+          "none": "Off",
+          "cupboard": "Cupboard",
+          "30": "30 min",
+          "60": "1 hr",
+          "90": "1 hr 30",
+          "120": "2 hr",
+          "180": "3 hr",
+          "240": "4 hr"
+        }
       }
     },
     "sensor": {

custom_components/localthings/translations/en.json

@@ -119,6 +119,18 @@
           "02": "2x",
           "03": "3x"
         }
+      },
+      "washer_dry_level": {
+        "state": {
+          "none": "Off",
+          "cupboard": "Cupboard",
+          "30": "30 min",
+          "60": "1 hr",
+          "90": "1 hr 30",
+          "120": "2 hr",
+          "180": "3 hr",
+          "240": "4 hr"
+        }
       }
     },
     "sensor": {