Merge Go frontend (apiserver + xcecli) into meson build

src/frontend/apiserver/backend/auth/provider.go

@@ -0,0 +1,14 @@
+package auth
+
+// UserRoleSeeder is an optional interface for providers that can enumerate all users.
+// Used to pre-populate the role store at startup so permissions work after restart.
+type UserRoleSeeder interface {
+	AllUsers() []string
+}
+
+// AuthProvider is the interface for authentication strategies.
+type AuthProvider interface {
+	Authenticate(username, password string) error
+	GetUserRoles(username string) []string
+	Name() string
+}