fix(auth): enforce dashboard authorization and improve team deletion

Add authorization gates to Project and Server creation buttons in the dashboard to prevent non-admin users from accessing resource creation. Improve team deletion to clear cache before deletion and automatically switch to the user's next available team.

- Hide create buttons from non-admin users in dashboard
- Clear cache before team deletion to prevent stale session resolution
- Switch user session to next available team when current team is deleted
- Handle refreshSession when user has no remaining teams
- Add tests for dashboard authorization enforcement and team deletion flow

bootstrap/helpers/shared.php

@@ -186,6 +186,14 @@ function refreshSession(?Team $team = null): void
             $team = User::find(Auth::id())->teams->first();
         }
     }
+
+    if (! $team) {
+        session()->forget('currentTeam');
+        Cache::forget('team:'.Auth::id());
+
+        return;
+    }
+
     // Clear old cache key format for backwards compatibility
     Cache::forget('team:'.Auth::id());
     // Use new cache key format that includes team ID