Add cpu_temp_raw_smoothed() (cmd.cpp/cmd.h): 256-sample average over a
slow EMA (alpha=0.15) so the RP2350 on-die temperature converges to the
true value instead of chasing per-sample 12-bit ADC noise (~1 LSB =
0.47 C). Single source of truth, ADC initialised in one place.
Also export CPU/Clock telemetry on HID feature report 0xfc (set_khz,
cached real_khz, vreg code, ADC ch4 raw). The handler is dormant: live
read over WebHID is not feasible (Chrome requires the report declared
in the HID descriptor, and declaring the OLED Edition vendor reports
breaks DualSense enumeration on Windows). It is harmless and left for a
possible future non-WebHID consumer. Link hardware_adc.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
