Windows autoscale: idle-clock test can't tell a preserved clock from a reset one #119

Follow-up to #118 (from the DeepSeek review there).

tests\windows_pools_test.ps1 checks that a refused shrink, and a GitHub outage, keep the pool's idle clock by matching .windows-autoscale-state against ^as \d+$. That also matches a clock reset to now, so a regression that restarts the idle countdown after every refusal would pass. The code is correct today: Invoke-AutoscalePass loads since from the saved state before comparing. Only the test is too weak.

• Assert the exact state line is unchanged after a refused shrink and after an outage.
• windows/README.md: note the API cost of autoscale passes, and how to see the real error behind "could not ask GitHub".