The hash was hardcoded independently in nix/packages/frontend.nix,
nix/packages/swarm-ui.nix, and nix/checks.nix's inline
swarm-ui-typecheck derivation, all three building from the one
frontend/package-lock.json. Nothing enforced the three copies staying
in sync, and on a recent PR only some of them got updated when the
lockfile changed.
Moved the hash into a new file, frontend/npm-deps-hash (plain text, no
trailing newline, co-located with package-lock.json so it reads as
the lockfile's other half), and all three derivations now
builtins.readFile it instead of hardcoding their own copy. A lockfile
change now only needs prefetch-npm-deps + one file overwrite; the
other two derivations pick it up automatically.
Verified: nix eval against all three derivations' npmDepsHash
attribute (eval-only, not a build) confirms all three resolve to the
same value read from the one file.
2a67cc0e69