feat: room list and live map over the local P2P channel

[hclaria]

What

Adds the room list (with names) and the live floor map for mqtt=False devices like the S1 Pro. These devices expose neither on any DPS nor on the biz/ MQTT stream, so today the room dropdown is empty and the map camera stays blank.

How

• New api/p2p/: opens the encrypted Tuya P2P map channel on the LAN with the device local key, runs the ICE/KCP handshake, and decodes the map stream. Pure asyncio, no new dependency. The channel and how to open it are documented in docs/P2P_MAP_CHANNEL.md.
• The coordinator fetches the RTC config (device_password + ICE servers) from Tuya Cloud, runs one P2P session in the background on local connect, then:
  • fills data.rooms (room select enabled for local devices);
  • builds a MapData and feeds the existing map camera, so camera.<device>_map now works on local Tuya devices too.

Tested

• End to end on an S1 Pro (T2080A, fw 7.0.170): 8 rooms and the rendered floor map show up live in HA, using the Tuya Cloud RTC config and LAN P2P, no capture involved.
• Unit tests in tests/test_p2p.py: framing, KCP tag, room decode (keeps room id 0).

Notes

• The device streams the real-time map only while moving; at rest it sends the room outline, which is enough to render a floor plan (the base is synthesized from it).
• Live robot position and cleaning path ride the same channel and could follow.