refactor: finish whitelist-to-allowlist rename in imgcache

internal/imgcache/imgcache.go

@@ -75,7 +75,7 @@ type ImageRequest struct {
 	Quality int
 	// FitMode is how to fit the image into requested dimensions
 	FitMode FitMode
-	// Signature is the HMAC signature for non-whitelisted hosts
+	// Signature is the HMAC signature for non-allowlisted hosts
 	Signature string
 	// Expires is the signature expiration timestamp
 	Expires time.Time
@@ -163,10 +163,10 @@ type SignatureValidator interface {
 	Generate(req *ImageRequest) string
 }
 
-// Whitelist checks if a URL is whitelisted (no signature required)
-type Whitelist interface {
-	// IsWhitelisted returns true if the URL doesn't require a signature
-	IsWhitelisted(u *url.URL) bool
+// Allowlist checks if a URL is allowlisted (no signature required)
+type Allowlist interface {
+	// IsAllowlisted returns true if the URL doesn't require a signature
+	IsAllowlisted(u *url.URL) bool
 }
 
 // Storage handles persistent storage of cached content