v1.6.0 — Python Quality Refactoring

What's Changed

Structural refactoring for code quality — no behavioral changes.

Highlights

• Generic field syncer — _sync_performers, _sync_tags, _sync_collection unified into a single sync_field() function with FieldSyncSpec dataclass, eliminating ~160 lines of duplication
• Decomposed processor.py — Extracted MetadataUpdater class (261 lines) and field_sync module (151 lines), reducing processor.py from 1293 to 854 lines
• DRY Pydantic validators — Three near-identical sanitize validators replaced with a factory function
• Import consolidation — Pure-function imports moved to module level; remaining lazy imports annotated with reasons
• Test modernization — Builder factories (make_plex_item, make_config, make_job, make_stash_scene) replace rigid fixtures; parametrized field sync tests cover all three field types

Stats

Metric	Before	After
processor.py lines	1293	854
Test coverage	~88%	90%
Tests	1223	1212

Test count decreased by 11 (redundant tests removed, 45 new tests added for extracted modules).

New Files

• worker/field_sync.py — Generic field sync logic
• worker/metadata_updater.py — Metadata update orchestration
• worker/errors.py — Base error classes (extracted to break circular import)
• tests/factories.py — Reusable test object builders