docs(release): include CPU sampling fix in 0.11.2

[caezium]

Summary

Update the prepared 0.11.2 release notes after merging #340 so the release accurately includes the CPU sampling correction from engine commit a6d1a98.

• make CPU accuracy a primary 0.11.2 highlight
• explain the baseline, pre-fan-out sampling, and summed-tick fix
• disclose the roughly 600 ms cost for cold one-shot status commands and that continuous GUI sampling adds no wait
• regenerate the homepage and release history

The first v0.11.2 run was canceled during compilation, before signing, notarization, GitHub release creation, appcast publication, or Homebrew publication. The unpublished tag was removed and will be recreated only after this PR merges.

Verification

• engine go test ./...
• python3 -m unittest discover -s scripts/tests (36 tests)
• node --test scripts/tests/test_site_analytics.mjs (7 tests)
• greenlight preflight macos --exit-code (GREENLIT)
• python3 scripts/site-release.py --check
• plutil -lint macos/Resources/Info.plist
• git diff --check