refactor: address third-pass review nits

- CreateUser: provision the default workspace OUTSIDE the signup DB transaction
  so CreateWorkspace's cache-forget / Stripe-quantity sync never runs inside a
  transaction (consistent with WorkspaceController::store); user+account stay
  atomic and a failed workspace create degrades to /workspaces/create.
- BillingController::swapToYearly: explicit null guard on the resolved
  subscription before dereferencing stripe_price.
- UsageController: reuse the already-loaded workspaces collection for the count
  instead of issuing a second query.
- Add a GitHub OAuth-callback test covering the default-workspace auto-create
  (mirrors the Google one).

app/Actions/User/CreateUser.php

@@ -21,8 +21,9 @@ class CreateUser
      */
     public static function execute(array $data, array $utmParameters = []): User
     {
-        $user = DB::transaction(function () use ($data, $utmParameters): User {
-            $isInviteRegistration = data_get($data, 'is_invite', false);
+        $isInviteRegistration = (bool) data_get($data, 'is_invite', false);
+
+        $user = DB::transaction(function () use ($data, $utmParameters, $isInviteRegistration): User {
             $requiresCardForTrial = (bool) config('trypost.billing.require_card_for_trial', true);
             $accountAttributes = [
                 'name' => data_get($data, 'name')."'s Account",
@@ -49,13 +50,13 @@ public static function execute(array $data, array $utmParameters = []): User
 
             $account->update(['owner_id' => $user->id]);
 
-            if (! $isInviteRegistration) {
-                CreateWorkspace::execute($user, ['name' => data_get($data, 'name')."'s Workspace"]);
-            }
-
             return $user;
         });
 
+        if (! $isInviteRegistration) {
+            CreateWorkspace::execute($user, ['name' => data_get($data, 'name')."'s Workspace"]);
+        }
+
         if (PostHogService::isEnabled()) {
             SyncUser::dispatch((string) $user->id);
         }

app/Http/Controllers/App/BillingController.php

@@ -130,6 +130,8 @@ public function swapToYearly(Request $request): RedirectResponse
 
         $subscription = $account->subscription(Account::SUBSCRIPTION_NAME);
 
+        abort_if($subscription === null, SymfonyResponse::HTTP_UNPROCESSABLE_ENTITY, 'No active subscription');
+
         if ($subscription->stripe_price === $yearlyPriceId) {
             return redirect()->route('app.billing.index');
         }

app/Http/Controllers/App/Settings/UsageController.php

@@ -35,7 +35,7 @@ public function index(Request $request): Response|RedirectResponse
 
         return Inertia::render('settings/account/Usage', [
             'usage' => [
-                'workspaceCount' => $account->workspaces()->count(),
+                'workspaceCount' => $account->workspaces->count(),
                 'socialAccountCount' => $totalSocialAccounts,
                 'memberCount' => $totalMembers,
                 'creditsUsed' => BillingCycle::for($account)->usedCredits(),

tests/Feature/SocialLoginControllerTest.php

@@ -72,6 +72,33 @@
     $this->assertAuthenticatedAs($user);
 });
 
+test('github callback creates new user with a default workspace', function () {
+    $socialiteUser = new SocialiteUser;
+    $socialiteUser->map([
+        'id' => '987',
+        'name' => 'New Dev',
+        'email' => 'newdev@example.com',
+    ]);
+
+    Socialite::shouldReceive('driver')
+        ->with('github')
+        ->andReturn($driver = Mockery::mock());
+    $driver->shouldReceive('user')->andReturn($socialiteUser);
+
+    $response = $this->get(route('auth.github.callback'));
+
+    $response->assertRedirect(route('register.success'));
+
+    $user = User::where('email', 'newdev@example.com')->first();
+    expect($user)->not->toBeNull();
+    expect($user->github_id)->toBe('987');
+    expect($user->name)->toBe('New Dev');
+    expect($user->workspaces()->count())->toBe(1);
+    expect($user->workspaces()->first()->name)->toBe("New Dev's Workspace");
+    expect($user->current_workspace_id)->toBe($user->workspaces()->first()->id);
+    $this->assertAuthenticatedAs($user);
+});
+
 test('google callback marks unverified existing user as verified', function () {
     $user = User::factory()->create([
         'email' => 'unverified@example.com',