feat: add base url utility and update api endpoints

ragflow_web/src/utils/url.ts

@@ -0,0 +1,24 @@
+export const getBaseUrl = (): string => {
+  const url = process.env.UMI_APP_API_BASE_URL || '';
+  return url.replace(/\/+$/, '');
+};
+
+const isAbsoluteUrl = (u: string): boolean => {
+  if (!u) return false;
+  const lower = u.toLowerCase();
+  return (
+    lower.startsWith('http://') ||
+    lower.startsWith('https://') ||
+    lower.startsWith('data:') ||
+    lower.startsWith('blob:')
+  );
+};
+
+export const withBaseUrl = (input: string): string => {
+  if (!input) return input;
+  if (isAbsoluteUrl(input)) return input;
+  const base = getBaseUrl();
+  if (!base) return input;
+  if (input.startsWith('/')) return `${base}${input}`;
+  return `${base}/${input}`;
+};