* Fix all golangci-lint issues across the codebase
Resolve 77 lint issues reported by golangci-lint with gocritic, gocognit,
gocyclo, maintidx, dupl, mnd, unparam, ireturn, goconst, and errcheck
enabled. Net reduction of ~175 lines through shared helpers and
deduplication.
* Suppress staticcheck SA1019 for intentional deprecated field usage
The Storage.Path field is deprecated but still read for backwards
compatibility with existing configs that haven't migrated to the URL field.