fix(cli): use authClient in tanstack start when separate backend

Author: AmanVarshney01

apps/cli/templates/auth/better-auth/web/react/tanstack-start/src/middleware/auth.ts.hbs

@@ -1,3 +1,4 @@
+{{#if (eq backend "self")}}
 import { auth } from "@{{projectName}}/auth";
 import { createMiddleware } from "@tanstack/react-start";
 
@@ -9,4 +10,22 @@ export const authMiddleware = createMiddleware().server(async ({ next, request }
     return next({
         context: { session }
     })
-})
+})
+{{else}}
+import { authClient } from "@/lib/auth-client";
+import { createMiddleware } from "@tanstack/react-start";
+
+export const authMiddleware = createMiddleware().server(
+	async ({ next, request }) => {
+		const session = await authClient.getSession({
+			fetchOptions: {
+				headers: request.headers,
+				throw: true
+			}
+		})
+		return next({
+			context: { session },
+		});
+	},
+);
+{{/if}}