Harden env storage and add Codex URL resolution #132

Job	Run time
build-linux-host-simd	12m 5s
build (aarch64-unknown-linux-gnu, ubuntu-latest)	7m 1s
build (aarch64-apple-darwin, macos-latest)	4m 54s
build (x86_64-unknown-linux-gnu, ubuntu-latest)	4m 44s
build (x86_64-apple-darwin, macos-latest)	9m 9s
release	11s
	38m 4s

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