Refactor `uv-toolchain` types #7720

Job	Run time
build binary \| macos x86_64	1m 28s
build binary \| linux	2m 15s
build binary \| windows	2m 8s
build binary \| macos aarch64	1m 3s
cargo clippy \| ubuntu	51s
cargo clippy \| windows	1m 12s
cargo fmt	28s
cargo shear	23s
cargo test \| ubuntu	4m 6s
cargo test \| windows	5m 58s
Determine changes	9s
cargo test \| macos	3m 57s
check windows trampoline	2m 32s
benchmarks	4m 44s
check system \| homebrew python on macos aarch64	17s
check system \| python on macos aarch64	16s
check cache \| macos aarch64	11s
check system \| python on macos x86_64	24s
check system \| python3.13 on windows	1m 36s
check system \| embedded python3.10 on windows	34s
check system \| python3.12 via chocolatey	1m 31s
check system \| python3.10 on windows	50s
check system \| python3.10 on windows x86	58s
integration test \| conda on ubuntu	31s
integration test \| github actions	13s
ecosystem test \| prefecthq/prefect	28s
check cache \| ubuntu	47s
ecosystem test \| pallets/flask	10s
check system \| alpine	22s
check system \| amazonlinux	25s
check system \| python on debian	49s
check system \| conda3.8 on linux	41s
check system \| conda3.11 on linux	46s
check system \| python on fedora	47s
check system \| python on opensuse	44s
check system \| conda3.8 on windows	2m 39s
check system \| python via pyenv	1m 50s
check system \| conda3.11 on windows	2m 50s
check system \| conda3.8 on macos	41s
check system \| pypy on ubuntu	32s
check system \| pyston	3m 50s
check system \| conda3.11 on macos	43s
check system \| python on rocky linux 8	33s
check system \| python on rocky linux 9	24s
check system \| python on ubuntu	21s
	58m 57s

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