feat(frontend): Finalize auth refactor, routing, and resolve all code review findings

frontend/src/services/auth.ts

@@ -38,6 +38,11 @@ export const AuthService = {
 
   async getMe(): Promise<UserResponse> {
     const response = await api.get<UserResponse>("/auth/me")
+    // Double check that we got JSON and not an HTML fallback
+    const contentType = response.headers["content-type"]
+    if (contentType && !contentType.includes("application/json")) {
+      throw new Error("Invalid response from server")
+    }
     return response.data
   },