CHANGES
* Define `getGoVersion` function in `flake.nix`.
* Use `getGoVersion` to set Go version consistently.
* Pass `goVersion` explicitly into `nix/shell.nix`.
* Remove redundant Go version definition from `shell.nix`.
Update Go version across Dockerfile, Nix configurations, and Go modules.
Refresh dependencies and Nix flake inputs.
CHANGES:
* Update Go version to 1.24.2 in Dockerfile.
* Set Go version to 1.24.0 and toolchain to 1.24.2.
* Refresh Go module dependencies and sums (go.mod, go.sum).
* Update Nix flake lock file inputs.
* Configure Nix environment and packages for Go 1.24.
* Update gomod2nix lock file with dependency hashes.
* Use Go 1.24 in Nix development shell environment.
