Add Convex client setup and authentication handling

- Introduced a new module for Convex client configuration in `src/modules/convex.ts`.
- Implemented an authentication token fetcher to manage user tokens.
- Integrated the Convex client into the AuthProvider component in `src/pages/auth/index.tsx`.

src/modules/convex.ts

@@ -0,0 +1,32 @@
+import { api } from "@kevisual/convex";
+import { ConvexClient, AuthTokenFetcher, ConvexHttpClient } from "convex/browser";
+const url = localStorage.getItem("CONVEX_URL") || 'https://convex.kevisual.cn'
+const client = new ConvexClient(url!);
+const httpClient = new ConvexHttpClient(url!);
+export const initConvex = async () => {
+  const getToken = async () => {
+    const token = localStorage.getItem("token");
+    if (!token) {
+      return null;
+    }
+    const res = await httpClient.action(api.token.create, { token: token! });
+    if (res.code === 200) {
+      return res.data.accessToken;
+    }
+    return null;
+  }
+  const authTokenFetcher: AuthTokenFetcher = async ({ forceRefreshToken }: { forceRefreshToken: boolean }) => {
+    console.log("AuthTokenFetcher called, forceRefreshToken:", forceRefreshToken);
+    if (forceRefreshToken) {
+      const token = await getToken();
+      // console.log("fetch got token:", token);
+      return token;
+    }
+    return null;
+  }
+  client.setAuth(authTokenFetcher, (isAuthenticated) => {
+    console.log("Auth isAuthenticated:", isAuthenticated);
+  });
+}
+
+export { client, httpClient };