fix(winpython): narrow search paths and add discovery cache #1502

Job	Run time
Tests (ubuntu-latest, x86_64-unknown-linux-musl, yes)	9m 51s
Tests in Containers (ci-homebrew-container, ubuntu-latest, homebrew/brew, x86_64-unknown-linux-musl)	3m 54s
Tests in Containers (ci-jupyter-container, ubuntu-latest, mcr.microsoft.com/devcontainers/univers...	7m 14s
Env Tests (ci-poetry-project, windows-latest, x86_64-pc-windows-msvc)	5m 56s
Builds (windows-latest, aarch64-pc-windows-msvc)	6m 56s
Env Tests (ci-poetry-project, ubuntu-latest, x86_64-unknown-linux-musl)	3m 10s
Env Tests (ci-poetry-custom, windows-latest, x86_64-pc-windows-msvc)	5m 43s
Tests (windows-latest, x86_64-pc-windows-msvc, yes)	8m 40s
Env Tests (ci-poetry-global, windows-latest, x86_64-pc-windows-msvc)	7m 37s
Tests (macos-latest, x86_64-apple-darwin, yes)	16m 37s
Tests (macos-14, aarch64-apple-darwin, yes)	14m 38s
Env Tests (ci-poetry-custom, ubuntu-latest, x86_64-unknown-linux-musl)	2m 56s
Env Tests (ci-poetry-global, ubuntu-latest, x86_64-unknown-linux-musl)	2m 43s
Builds (ubuntu-latest, x86_64-unknown-linux-musl, yes)	2m 32s
Builds (windows-latest, x86_64-pc-windows-msvc)	4m 59s
Builds (macos-14, aarch64-apple-darwin, yes)	3m 13s
Builds (macos-latest, x86_64-apple-darwin, yes)	3m 37s
	1h 50m 16s

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