Add MG2-6HW breathing mmWave radar (#6262)
## Summary
- Adds a device config for the MG2-6HW breathing millimeter-wave radar
(Tuya product `ammxeuwjrvo3rjyd`, category `hps`). The device reports
hardware `R60A`, i.e. the MicRadar R60ABD1 sleep monitoring module
([manual](https://en.micradar.cn/uploads/soft/20250314/1741943164.pdf)).
- Maps presence, motion, heart rate, breath rate, distance, in-bed
occupancy, sleep state, the reporting switches, struggle detection and
the unoccupied timer from the thing model.
- Sleep totals, ratios, 10-minute averages and firmware strings are
diagnostic entities.
## Test plan
- [x] Config validated against `device_config_schema.json`
- [x] Added on a live device over local protocol 3.4 (Tuya Local
2026.9.1)
- [x] Occupancy, in bed, motion, heart rate, breath rate, distance and
sleep statistics report live values
- [ ] This unit does not send DP 109, 153, 156 or 159 while the related
features are off; those entities stay optional
Manufacturer is not printed in the cloud product record, so the config
lists the model only.
Made with [Cursor](https://cursor.com)
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Co-authored-by: Jason Rumney <make-all@users.noreply.github.com>