docs: CHANGELOG v0.13.0 - exhaustive: dead reasonTimeout enum value - dupword: duplicate "agent" in help text - staticcheck SA5011: nil deref after os.Exit - File permissions: full ~/.cmdguard tree → 0600/0700 - Go 1.22–1.26 modernisation (CutPrefix, SplitSeq, slices.Contains, …) - .golangci.yml: 5 → 37 linters