- Move stored_integration_config(), build_audiobookshelf_config() to domain/settings_core.py
- Remove legacy fallback from stored_integration_config() (only config[integrations])
- Add load_audiobookshelf_config() as combined entry point
- PostConversionHooks reads config directly via stored_integration_config()
- WebUI imports from domain/settings_core instead of webui/routes/utils/settings
- Remove duplicate _build_abs_config() from PostConversionHooks
- Remove dead audiobookshelf code from infrastructure/exporters.py
- Remove duplicate audiobookshelf functions from webui/service.py
- Fix OutputFormat enum serialization in output_layout_service.py and conversion_executor.py
(f'{enum}' gave 'OutputFormat.WAV' instead of '.wav')
- Mock spaCy in test_returns_at_least_one_segment instead of loading real model
- Add 28 tests for PostConversionHooks and build_audiobookshelf_config
