feat: Implement admin settings UI, enhance admin authentication with password hashing, and add new streaming runtime logic for Claude and OpenAI adapters with extensive compatibility tests.

internal/admin/request_error.go

@@ -0,0 +1,23 @@
+package admin
+
+import "errors"
+
+type requestError struct {
+	detail string
+}
+
+func (e *requestError) Error() string {
+	return e.detail
+}
+
+func newRequestError(detail string) error {
+	return &requestError{detail: detail}
+}
+
+func requestErrorDetail(err error) (string, bool) {
+	var reqErr *requestError
+	if errors.As(err, &reqErr) {
+		return reqErr.detail, true
+	}
+	return "", false
+}