feat(auth): add google sign-in onboarding flow

src/api/client.ts

@@ -52,7 +52,7 @@ export class ApiError extends Error {
 
 const cleanBaseUrl = API_BASE_URL.replace(/\/+$/, "")
 
-const buildUrl = (endpoint: string) => {
+export const buildApiUrl = (endpoint: string) => {
   const cleanEndpoint = endpoint.startsWith("/") ? endpoint : `/${endpoint}`
   return `${cleanBaseUrl}${cleanEndpoint}`
 }
@@ -154,7 +154,7 @@ const refreshAccessToken = async () => {
 
   if (!refreshRequest) {
     refreshRequest = (async () => {
-      const response = await fetch(buildUrl("/api/users/token/refresh/"), {
+      const response = await fetch(buildApiUrl("/api/users/token/refresh/"), {
         method: "POST",
         headers: {
           "Content-Type": "application/json",
@@ -226,7 +226,7 @@ export const authFetch = async (endpoint: string, options: RequestInit = {}, all
     ...options.headers,
   }
 
-  const response = await fetch(buildUrl(endpoint), {
+  const response = await fetch(buildApiUrl(endpoint), {
     ...options,
     headers,
   })

src/api/users.ts

@@ -1,4 +1,4 @@
-import { authFetch, buildApiError } from './client';
+import { authFetch, buildApiError, buildApiUrl } from './client';
 
 // --- Auth Endpoints ---
 
@@ -28,8 +28,72 @@ export const loginWithOtp = async (mobile: string, otp: string) => {
   if (!response.ok) throw await buildApiError(response);
   return response.json();
 };
-
-export const logoutUser = async (refreshToken: string) => {
+
+export const startGoogleLogin = () => {
+  window.location.assign(buildApiUrl("/api/users/oauth/google/start/"));
+};
+
+export type GoogleOAuthFlowResponse =
+  | {
+      status: "authenticated";
+      access: string;
+      refresh: string;
+    }
+  | {
+      status: "collect_mobile";
+      email: string;
+      first_name: string;
+      last_name: string;
+      avatar_url: string;
+    }
+  | {
+      status: "claim_required";
+      mobile: string;
+      detail?: string;
+    };
+
+export const getGoogleOAuthFlow = async (flow: string): Promise<GoogleOAuthFlowResponse> => {
+  const response = await authFetch(`/api/users/oauth/google/flow/?flow=${encodeURIComponent(flow)}`, {
+    method: "GET",
+  });
+  if (!response.ok) throw await buildApiError(response);
+  return response.json();
+};
+
+export const completeGoogleOAuthSignup = async (
+  flow: string,
+  mobile: string,
+): Promise<GoogleOAuthFlowResponse> => {
+  const response = await authFetch("/api/users/oauth/google/complete/", {
+    method: "POST",
+    body: JSON.stringify({ flow, mobile }),
+  });
+  if (!response.ok) throw await buildApiError(response);
+  return response.json();
+};
+
+export const sendGoogleOAuthClaimOtp = async (flow: string) => {
+  const response = await authFetch("/api/users/oauth/google/claim/send-otp/", {
+    method: "POST",
+    body: JSON.stringify({ flow }),
+  });
+  if (!response.ok) throw await buildApiError(response);
+  return response.json();
+};
+
+export const verifyGoogleOAuthClaim = async (
+  flow: string,
+  code: string,
+): Promise<GoogleOAuthFlowResponse> => {
+  const response = await authFetch("/api/users/oauth/google/claim/verify/", {
+    method: "POST",
+    body: JSON.stringify({ flow, code }),
+  });
+  if (!response.ok) throw await buildApiError(response);
+  return response.json();
+};
+
+export const logoutUser = async (refreshToken: string) => {
   const response = await authFetch('/api/users/logout/', {
     method: 'POST',
     body: JSON.stringify({ refresh: refreshToken })