`get_all_downloads` was calling `engine.get_all_records()` — a method that
doesn't exist on DownloadEngine. Same story for `cancel_record` and
`clear_completed`. The engine exposes `iter_records_for_source`, `get_record`,
`update_record`, and `remove_record` — matching what every other streaming
client (Deezer, HiFi, Qobuz, SoundCloud, Tidal, YouTube) already uses.
With `get_all_downloads` silently returning `[]` on every call (the missing
method raised, `except Exception: return []` swallowed it), the download monitor
never saw Amazon records as complete — tasks stayed stuck at 0% even after the
file had fully downloaded.
Changes:
- `get_all_downloads` → `iter_records_for_source('amazon')`
- `get_download_status` → `get_record('amazon', id)`, no try/except
- `cancel_download` → `get_record` check + `update_record` (Cancelled) +
optional `remove_record` — same pattern as deezer/hifi/etc
- `clear_all_completed_downloads` → iterate + `remove_record` for terminal
states; returns True on no-engine (nothing to clear = success)
- `_record_to_status` drops the `download_id` argument; reads `rec['id']`
instead (worker stores `'id'` in every record — `iter_records_for_source`
returns the full record dict)
Tests updated to match: `iter_records_for_source` mock replaces
`get_all_records`, cancel test verifies `update_record`+`remove_record`,
clear test verifies only terminal-state records are removed, graceful-error
test replaced with no-records boundary test (exception propagation is handled
at the engine aggregator layer, not per-plugin).
Broque Thomas