- Implement services/cloud_analysis_processing.py with full pipeline:
queued -> downloading -> extracting -> classifying -> indexed
- Stale guard: version key comparison fires before provider byte fetch (T-14-13)
- Cache pin lifecycle: pin acquired before bytes used, released in finally block (T-14-12)
- No provider mutation methods called: adapter only used via get_object (T-14-03)
- No local Document row created: classification targets CloudItem directly
- Cooperative cancellation check at job/item level before each stage
- ProcessingResult dataclass with status, cache_entry_id, error_code fields
- Add 4 contract tests: status_transitions, stale_detection, pin_release, no_mutations