- Remove import from app.plugins.builtins.test_sample (deleted in Phase 4)
- Define SamplePlugin inline in test_plugins.py with same lifecycle behavior
- Replace all test_sample/TestSamplePlugin references with sample_plugin/SamplePlugin
- Create migration SQL files: 0001_sample_plugin.sql, 0001_bad_migration.sql
- Update discover_builtins test to check for tags plugin instead