v2.1.0 — HT25G2 Gen2, RSSI/status sensors, BLE proxy hardening

New devices

• HT25G2-0001 (Gen2 hose-tap, fw0111) — protobuf-protocol valve support. Thanks @exactmike (#11).
• HT34-0001 (fw0058) — now routed to the XD protobuf class alongside HT34A-0001.

New entities

• Signal strength (RSSI) sensor, read from Home Assistant's bluetooth manager so it reports even while disconnected (disabled by default).
• Connected and Watering binary sensors per device.
• Battery sensors are now created for every BLE timer instead of being gated on a cloud-cached value (BT-only devices the cloud never primed now get them).

Reliability

• Marginal-link hardening: the BLE handshake is now bounded with a timeout and the open is retried a few times, so a weak ESPHome-proxy link fails cleanly instead of wedging the connection.
• Capped write-ack: the ATT Write Response wait is capped — the device acks via notification, not a write response, and some transports never relay the absent response. The notification drain is the real ack.
• HT25 re-bind per command: actuation now re-runs the bind/init before every START/STOP, so a stale pooled bind can't silently drop a watering command (~1.2 s extra latency per actuation).
• HT34A status confirmation: battery + watering-status decode, with retry-and-confirm start/stop that verifies the real device state.

Other

• probe_send debug service for sending arbitrary inner-plaintext frames during protocol work.

Notes

• HT34A / HT34 actuation is not verified on hardware — treat as experimental.
• Most of the reliability and sensor work was ported from @stuartdenne's fork; Gen2 device support is from @exactmike.

Full changelog: v2.0.6...v2.1.0