Add server ownership, team access, role-based UI, and default admin role

- New migration 002_server_access.sql: created_by column + server_user table
- Server model: ownership, permission checks, team management methods
- Routes: /team routes, RoleMiddleware on /servers/create and /admin
- ServerController: permission checks via server_user, team CRUD methods
- TerminalController: server access checks
- DashboardController: filter servers by accessible ones
- ApiController: server access checks
- Views: team.php, team_server.php, sidebar Team link, hide actions by role
- Default user role changed from operator to admin on registration
- Admin user form defaults to admin role

src/Controllers/TerminalController.php

@@ -32,6 +32,11 @@ class TerminalController
             $this->view->error(404);
         }
 
+        $userId = (int) Session::get('user_id');
+        if (!$this->serverModel->canView($id, $userId)) {
+            $this->view->error(404);
+        }
+
         $commandHistory = new CommandHistory();
         $history = $commandHistory->getByServer($id, 50);
 
@@ -50,6 +55,11 @@ class TerminalController
             $this->view->json(['success' => false, 'message' => 'Server not found'], 404);
         }
 
+        $userId = (int) Session::get('user_id');
+        if (!$this->serverModel->canView($id, $userId)) {
+            $this->view->json(['success' => false, 'message' => 'Forbidden'], 403);
+        }
+
         $command = $_POST['command'] ?? '';
 
         if (empty($command)) {