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/book_matching_test.go

@@ -34,7 +34,7 @@ func TestBookMatchingQueryBooks(t *testing.T) {
 	})
 
 	t.Run("QueryBooks_WithAuth_ByTitle", func(t *testing.T) {
-		_ = createTestMediaItemID(t, setup.Server, token)
+		_ = createTestMediaItemID(t, setup.Server)
 
 		req := map[string]interface{}{
 			"title": "Test Ebook",
@@ -157,7 +157,7 @@ func TestBookMatchingBulkLink(t *testing.T) {
 	})
 
 	t.Run("BulkLinkBooks_InvalidUnlinkedBookID", func(t *testing.T) {
-		bookID := createTestMediaItemID(t, setup.Server, token)
+		bookID := createTestMediaItemID(t, setup.Server)
 
 		req := map[string]interface{}{
 			"links": []map[string]interface{}{