refactor: prove `Int.bmod_k_eq` without `omega`

This PR rewrites the proof of `Int.bmod_k_eq` so that it no longer relies on non-terminal `simp` calls followed by `omega`, and drops the `Init.Omega` import from `Init.Data.Int.Kernel`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
1 file changed