Pin lint CI Go version to go.mod

Using `go-version: stable` resolved to Go 1.26, but go.mod declares
go 1.24.0. golangci-lint was picking up a file from the Go 1.26
toolchain's own vendor directory:

  golang.org/x/crypto/chacha20poly1305/fips140only_go1.26.go

This file has a `//go:build go1.26` constraint, which causes a typecheck
failure when the module is built with go 1.24. That failure cascades
into false-positive errors across the codebase.

Switching to `go-version-file: go.mod` pins CI to the Go version
declared in go.mod, ensuring toolchain and module version stay in sync.

Author: dineshudayakumar

.github/workflows/lint.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
-          go-version: stable
+          go-version-file: go.mod
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v7
         with: