Step 5 (health): temperatures in status.temps

- aes67_health: status.temps = [{name, c, min_c, max_c, warn_c}]
  (0.1 °C), sampled every 2 s by a health task. On-die "SoC" sensor via
  driver/temperature_sensor.h, range 20..100 °C, warn at 85 °C.
  health_temp_register(name, read_cb, warn_c) for board sensors.
  Warning logged when crossing warn_c, cleared below warn_c - 5 °C.
- Verified: SoC 26-28 °C at idle with min/max since boot; with a
  temporary 27 °C threshold the warning was logged and arrived via
  syslog as <132>, status carried warn_c 27.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/aes67-core-base.md

@@ -33,6 +33,7 @@ Reference devices for UI and defaults: Riedel Bolero (PTP status), Riedel Direct
 ## Temperatures
 - `status.temps` = array of {name, c, min_c, max_c, warn_c}; min/max since boot, warn_c optional. Any number of sensors; the UI renders one row per sensor and marks HIGH (red) at or above warn_c.
 - ESP32-P4: on-die sensor via the `temperature_sensor` driver (driver/temperature_sensor.h). Pick the measurement range to suit (e.g. -10..80 °C), sample every ~2 s in the health task, and report it as "SoC". It measures the die, not ambient: expect it to read well above room temperature.
+  - Implemented with range 20..100 °C (±2 °C; the warning level must lie inside the range), warn_c 85 °C. On the test board the die reads ~27 °C at idle in a cool room.
 - Boards may add external sensors (e.g. I2C) by appending to the same array; the project or board component registers them.
 - Log a warning (goes to syslog) when crossing warn_c, with hysteresis (e.g. clear at warn_c - 5).