C1: SwitchDesc MQTT discovery now emits payload_on/off='On'/'Off',
state_on/off='On'/'Off', and a Jinja2 boolean-to-string value_template
so HA can correctly interpret and command switch entities.
C2: POWER write_fn corrected — path is ['power','vs','0'] segment list
(not a single slash-prefixed string), and payload comparison is
p == 'On' (not truthiness) so 'Off' can actually be sent.
I2: Golden regression oracle strengthened to exact equality for both
state_keys and discovery_unique_ids; prior subset-only check allowed
over-production to go undetected. Two golden tests now fail revealing
stale fixtures (dishwasher: +3 keys; refrigerator: +9 keys) — fixtures
intentionally NOT updated, human review required.