Mobile transfers: list, add via URL/magnet, progress and actions #26

Part of #14 (W3 — mobile v1). Blocked by the shell + auth slices.

Outcome

Users see and control their transfers — the put.io core loop's other half: add a link, watch it land, open the file.

Scope

• Transfer list with live-ish status (poll or refresh cadence per contract), progress, speeds, ETA; SDK transfers namespace is already complete — feat(mobile): add transfer management #73 (5 s visible-only polling, row reconciliation, speeds/ETA/availability copy)
• Add transfer: URL/magnet input; this is also the landing point for the share-target slice — feat(mobile): add transfer management #73 (TransfersEvent.Add, validation copy); share-target entry stays under Mobile share and open-in: share target, deep links, share out #29
• Per-transfer actions: cancel, retry, clean finished; navigate to resulting file when done — feat(mobile): add transfer management #73 (explicit reducer events, confirmed Cancel/Clean, Open resolves the file through Files)
• Clear conversion/availability messaging when a finished transfer's file still needs processing — feat(mobile): add transfer management #73 (mobile_transfer_file_preparing / mobile_transfer_file_unavailable)

Acceptance criteria

• DoD: verify green; screen recording of add-magnet → progress → open-file on the harness attached