standardize mobile api transport for gyms and core services

apps/mobile/src/app/(auth)/onboarding.tsx

@@ -12,7 +12,7 @@ import {
 import { useUser, useAuth } from "@clerk/clerk-expo";
 import { useRouter } from "expo-router";
 import { fitnessProfileApi } from "@/api/fitnessProfile";
-import { API_BASE_URL } from "@/config/api";
+import { gymsApi, type Gym } from "@/api/gyms";
 import log from "../../utils/logger";
 
 export default function OnboardingScreen() {
@@ -20,9 +20,7 @@ export default function OnboardingScreen() {
   const { getToken } = useAuth();
   const router = useRouter();
   const [isSubmitting, setIsSubmitting] = useState(false);
-  const [gyms, setGyms] = useState<
-    Array<{ id: string; name: string; location?: string }>
-  >([]);
+  const [gyms, setGyms] = useState<Gym[]>([]);
   const [gymsLoading, setGymsLoading] = useState<boolean>(false);
   const [selectedGymId, setSelectedGymId] = useState<string | null>(null);
 
@@ -31,13 +29,8 @@ export default function OnboardingScreen() {
       try {
         setGymsLoading(true);
         const token = await getToken();
-        const res = await fetch(`${API_BASE_URL}/api/gyms`, {
-          headers: token ? { Authorization: `Bearer ${token}` } : undefined,
-        });
-        const data = await res.json();
-        if (Array.isArray(data)) {
-          setGyms(data);
-        }
+        const data = await gymsApi.getGyms(token);
+        setGyms(data);
       } catch (e) {
         log.error("Failed to fetch gyms", e);
       } finally {
@@ -82,14 +75,7 @@ export default function OnboardingScreen() {
       // If gym was selected or cleared, patch user's gym selection first
       // selectedGymId: string gym id, or null to proceed without gym
       try {
-        await fetch(`${API_BASE_URL}/api/users/gym`, {
-          method: "PATCH",
-          headers: {
-            "Content-Type": "application/json",
-            Authorization: `Bearer ${token}`,
-          },
-          body: JSON.stringify({ gymId: selectedGymId }),
-        });
+        await gymsApi.updateUserGym(selectedGymId, token);
       } catch (e) {
         log.warn("Failed to update gym selection", { gymId: selectedGymId });
       }