Support Elite and generic FTMS trainers

[ridecontrol]

Summary

• discover smart trainers by their advertised Bluetooth FTMS service instead of a Wahoo-specific name
• sequence FTMS control commands through their matching acknowledgements
• request control and start or resume the trainer before restoring resistance
• persist the selected trainer immediately and retain the legacy KICKR reconnect fallback
• document and test generic FTMS and Elite DIRETO XR-T support

Why

The trainer chooser only accepted device names beginning with KICKR, which excluded the Elite DIRETO XR-T before the shared FTMS implementation could run. Control writes also advanced after the BLE write completed instead of waiting for the FTMS control-point response, allowing stricter trainers to reject overlapping initialization commands.

Impact

Ride Control can pair with standards-compliant FTMS trainers from multiple manufacturers while continuing to use one active trainer for a ride. Protocol rejections now report the trainer's actual FTMS result.

Validation

• bun run ci
• 258 tests passed
• Biome completed with warnings treated as errors
• Tailwind diagnostics, TypeScript, and the production Vite build passed