Go Fix

Modernize Go code using go fix, rebuilt in Go 1.26 on the Go analysis framework. It applies safe rewrites toward newer language and stdlib idioms, respecting the module's declared Go version — it never rewrites code into something the module has not opted into via its go.mod.

What this skill does

1. Verifies the toolchain is Go 1.26 or later; stops if not.
2. Checks preconditions: a Go module and a clean git state.
3. Previews fixes with go fix -diff, applies them, and re-runs until no fixes remain (fixes can expose further fixes).
4. Verifies the result builds and tests pass, then reports what changed.

Toolchain check (required — do not skip)