fix: remove redundant getTestUserID call in TestKoboInitialization

The TestKoboInitialization test was calling getTestUserID() explicitly
on line 25, but loginTestUser() already calls this internally. This caused
the test user to be deleted and recreated after login, leading to
inconsistent state and HTTP 500 errors when creating libraries.

After removing the redundant call:
- TestKoboInitialization now passes
- All Kobo sync tests pass successfully

cmd/server/tests/kobo_test.go

@@ -22,7 +22,6 @@ func TestKoboInitialization(t *testing.T) {
 	setup := setupTestServer(t)
 
 	token := loginTestUser(t, setup.Server, setup.DB)
-	_ = getTestUserID(t, setup.DB)
 	_ = createTestMediaItemID(t, setup.Server, token)
 
 	log.Printf("[DEBUG] Kobo test setup: creating device and media")