v3.9 - Release audit fixes
Bug fixes found during release audit:
- Fix: GPU benchmark score log showed wrong MHz value. Runner used glob /sys/class/devfreq/*/max_freq - alphabetical order returns dmc (924 MHz) before ff400000.gpu (600 MHz), so logs showed GPU=924MHz instead of GPU=600MHz. Fixed to use name-pattern loop matching gpu/mali/ff400000.
- Fix: ValidateUndervolt() showed empty temperature fields when CPU stress thermal-aborted. StressTestCPU now exports partial temp stats before returning exit code 1.