chore: improve const maintainability #1264

Job	Run time
cargo fmt	16s
codespell	12s
cargo clippy	2m 8s
cargo doc	1m 41s
⚖️ Check third party licenses	4m 51s
ubuntu / stable / coverage	4m 3s
cargo shear (unused dependencies)	15s
tests as root	3m 58s
Unit test for embedded downloader	30s
Build release binaries	2m 26s
K8s integration tests (flux-self-update)	6m 25s
Unit, docs and onhost integration tests	7m 15s
K8s integration tests (part2)	5m 59s
K8s integration tests (part1)	8m 21s
build-windows-binary	4m 6s
security / Rust audit scanner	2m 37s
k8s-e2e-tests / K8s e2e tests infra	9m 31s
k8s-e2e-tests / K8s e2e tests	4s
🟢 All required checks and tests pass	4s
	1h 4m 42s

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