perf(pet-windows-registry): parallelize HKLM/HKCU walk and reuse cache across refresh #1515

Job	Run time
Tests (windows-latest, x86_64-pc-windows-msvc, yes)	9m 16s
Tests in Containers (ci-homebrew-container, ubuntu-latest, homebrew/brew, x86_64-unknown-linux-musl)	3m 49s
Builds (macos-14, aarch64-apple-darwin, yes)	2m 48s
Tests (ubuntu-latest, x86_64-unknown-linux-musl, yes)	9m 35s
Env Tests (ci-poetry-project, windows-latest, x86_64-pc-windows-msvc)	5m 48s
Builds (macos-latest, x86_64-apple-darwin, yes)	4m 0s
Env Tests (ci-poetry-global, ubuntu-latest, x86_64-unknown-linux-musl)	2m 57s
Tests (macos-14, aarch64-apple-darwin, yes)	11m 13s
Env Tests (ci-poetry-project, ubuntu-latest, x86_64-unknown-linux-musl)	2m 54s
Tests (macos-latest, x86_64-apple-darwin, yes)	16m 15s
Tests in Containers (ci-jupyter-container, ubuntu-latest, mcr.microsoft.com/devcontainers/univers...	4m 43s
Builds (ubuntu-latest, x86_64-unknown-linux-musl, yes)	2m 21s
Env Tests (ci-poetry-custom, windows-latest, x86_64-pc-windows-msvc)	6m 20s
Builds (windows-latest, aarch64-pc-windows-msvc)	5m 10s
Env Tests (ci-poetry-custom, ubuntu-latest, x86_64-unknown-linux-musl)	2m 52s
Builds (windows-latest, x86_64-pc-windows-msvc)	5m 11s
Env Tests (ci-poetry-global, windows-latest, x86_64-pc-windows-msvc)	8m 7s
	1h 43m 19s

Provide feedback