Discovery 2026-07-19: the Dell BIOS ships PL1=PL2=135W on this 45W-TDP
i7-10875H. With no sustained-power brake, the only thing that ever slows
the CPU is the 100C thermal limiter — which is how a set peaked at 91C and
had to be aborted. Percent clock caps (--cool's max_perf_pct) don't bound
multi-core power; watt caps do.

All three modes now set package power limits via RAPL, saved/restored by
--stop:
- --optimize / --extreme: PL1 45W (chip spec) / PL2 90W — full nominal
  performance, bursts stay snappy, sustained runaway impossible.
- --cool: PL1 28W / PL2 50W by default (~2.5GHz all-core), tunable with
  COOL_PL1_W / COOL_PL2_W.
- --diagnose now prints the current PL1/PL2 against spec.