fix(air_dresser): bind /buzzersound/vs/0 on the TP1_21 board (#208)

DA_DF_TP1_21_COMMON reports a plain {setBuzzerSound, supportedFinishSound}
buzzersound resource -- the same shape laundry.BUZZER_SOUND already
handles for washers/dryers -- but it was unbound because the air_dresser
registry never included that capability. Add it, and lock the board in
with a scrubbed fixture, golden, and capability tests.

The reporter's actual complaint (course cycles showing as raw codes) is
a labelling gap, not a coverage one: this board's course table has no
code->name mapping anywhere in the dump, same as issue #162's board, so
there's nothing to bind here -- it needs a reporter to identify the
codes before they can be named in translations.

custom_components/localthings/registry/by_type/air_dresser.py

@@ -1,7 +1,10 @@
 """AirDresser device registry (issue #162).
 
 Reuses washer/dryer/dishwasher's shared laundry surface -- job-beginning
-status, operational state, and diagnosis. air_dresser.py holds the two
+status, operational state, diagnosis, and (issue #208) the buzzer-sound
+select -- /buzzersound/vs/0's rep on this board is the plain
+{setBuzzerSound, supportedBuzzerSound} shape laundry.BUZZER_SOUND already
+expects, no AirDresser-specific wiring needed. air_dresser.py holds the two
 pieces specific to this device type: a minimal wrinkle-prevent-only
 /washer/vs/0 capability, and the course select's own translation key.
 """
@@ -17,6 +20,7 @@ REGISTRY = DeviceRegistry(
         air_dresser.AIR_DRESSER_SETTINGS,
         air_dresser.AIR_DRESSER_COURSE,
         air_dresser.AIR_DRESSER_SANITIZE,
+        laundry.BUZZER_SOUND,
         laundry.JOB_BEGINNING_STATUS,
         operational.OPERATIONAL_STATE,
         dishwasher.DIAGNOSIS,