Rename the candidate file validator to forbidden files

cmd/releasekit/internal/cli/config.go

@@ -154,7 +154,7 @@ type ValidationSettings struct {
 	// SharedFiles selects committed files relative to the repository root.
 	// Nil uses optional defaults; a non-nil empty slice selects no shared files.
 	SharedFiles    []string             `json:"shared_files"`
-	UntrackedFiles []string             `json:"untracked_files,omitempty"`
+	ForbiddenFiles []string             `json:"forbidden_files,omitempty"`
 	Go             GoValidationSettings `json:"go,omitempty"`
 	// GoFormat checks the formatting of committed regular Go source files.
 	// Omitted or false disables the check.