gofmt -r rewrite of all 506 interface{} occurrences to the any alias
(identical semantics), drop unused spec constants into comments, rename
unused parameters to _, convert three if-else chains to tagged
switches, and use slices.ContainsFunc for the private-IP check. No
behavior change; the whole package is now gofmt-clean.
Pure mechanical move within package gobackend — no signature or behavior
change. extension_providers.go (3,798 lines) now holds only the
extensionManager provider-listing/orchestration methods; DTOs, goja value
conversion, the provider wrapper methods, download fallback, and priority
state moved to extension_{provider_types,goja_convert,provider_wrapper,
fallback,priority}.go.
zarzet