refactor: use common mobile sdk for platform auth requests

mobile/lib/platformAuth.ts

@@ -1,5 +1,5 @@
 import { secureSessionStorage, clearMobileSessionStorage, MOBILE_SESSION_STORAGE_KEY } from '@/lib/secureSessionStorage';
-import { mobileRuntime } from '@/lib/runtime';
+import { createMobilePlatformSdk, mobileRuntime } from '@/lib/runtime';
 
 export interface PlatformAuthUser {
   id: string;
@@ -25,6 +25,10 @@ class PlatformAuthError extends Error {
   }
 }
 
+function createPlatformAuthSdk(accessToken: string | null = null) {
+  return createMobilePlatformSdk(() => accessToken);
+}
+
 function normalizeUser(value: any): PlatformAuthUser {
   return {
     id: String(value?.id || value?.sub || '').trim(),
@@ -43,13 +47,9 @@ async function platformRequest<T>(
     body?: Record<string, unknown>;
   }
 ): Promise<T> {
-  const response = await fetch(`${mobileRuntime.platformApiUrl}${path}`, {
+  const sdk = createPlatformAuthSdk(options?.accessToken ?? null);
+  const response = await sdk.fetch(path, {
     method: options?.method || 'GET',
-    headers: {
-      'Content-Type': 'application/json',
-      'x-product-id': mobileRuntime.productId,
-      ...(options?.accessToken ? { Authorization: `Bearer ${options.accessToken}` } : {}),
-    },
     body: options?.body ? JSON.stringify(options.body) : undefined,
   });
 
@@ -79,6 +79,10 @@ async function writeSession(session: StoredPlatformSession): Promise<void> {
   await secureSessionStorage.setItem(MOBILE_SESSION_STORAGE_KEY, JSON.stringify(session));
 }
 
+export async function persistPlatformSession(session: StoredPlatformSession): Promise<void> {
+  await writeSession(session);
+}
+
 export async function readPlatformSession(): Promise<StoredPlatformSession | null> {
   const raw = await secureSessionStorage.getItem(MOBILE_SESSION_STORAGE_KEY);
   if (!raw) {
@@ -119,6 +123,20 @@ export async function refreshPlatformSession(refreshToken: string): Promise<Stor
   return session;
 }
 
+export async function syncPlatformSessionFromTokens(
+  accessToken: string,
+  refreshToken: string
+): Promise<StoredPlatformSession> {
+  const user = await getCurrentPlatformUser(accessToken);
+  const session: StoredPlatformSession = {
+    accessToken,
+    refreshToken,
+    user,
+  };
+  await writeSession(session);
+  return session;
+}
+
 export async function restorePlatformSession(): Promise<StoredPlatformSession | null> {
   const stored = await readPlatformSession();
   if (!stored) {