fix: update test files for token handling and response parsing

- Update callers of createTestMediaItemID to not pass token
- Fix loginAdminUser to delete/recreate admin user for consistent state
- Fix TestListAllQueueItems_Admin to parse response as map with 'items' key
- Remove unused token variables from tests
- Update device_test.go with admin password hash constant

cmd/server/tests/analytics_test.go

@@ -266,7 +266,7 @@ func TestAnalyticsPopularBooks(t *testing.T) {
 
 	t.Run("GetPopularBooks_ResponseStructure", func(t *testing.T) {
 		// First create a book and some reading history
-		bookID := createTestMediaItemID(t, setup.Server, token)
+		bookID := createTestMediaItemID(t, setup.Server)
 
 		// Create reading history for the book
 		historyReq := map[string]interface{}{