Second sub-PR in the download orchestrator series. Strict 1:1 lift —
zero behavior change.
What moved:
- cancel_download (single slskd cancel) → cancel_single_download
- cancel_all_downloads (cancel + clear + sweep) → cancel_all_active
- clear_finished_downloads (slskd clear + sweep) → clear_finished_active
- clear_completed_downloads (local task tracker prune) → clear_completed_local
Slskd-touching helpers take (soulseek_client, run_async, sweep_callback)
explicitly so the route layer wires the live client + the existing
_sweep_empty_download_directories helper. The local-state helper imports
download_tasks/download_batches/batch_locks/tasks_lock straight from
core.runtime_state since those are module-level shared globals.
Prep change: `batch_locks` dict moved from web_server.py global into
core/runtime_state.py alongside the other download globals. web_server.py
re-imports from runtime_state so the ~3 existing call sites in
web_server.py keep resolving without modification. Identity preserved
(same dict across all importers).
Out of scope (deferred to PR4g batch lifecycle):
- cancel_download_task (calls _on_download_completed)
- cancel_task_v2 + _atomic_cancel_task + _find_task_by_playlist_track
(manipulate batch active_count directly, deeply coupled to lifecycle)
Behavior parity:
- Same response shapes + status codes on each route
- Same call order (cancel_all → clear_all_completed → sweep)
- Same conditional sweep on clear_finished (skipped on failure)
- Same sweep ALWAYS runs after cancel_all even if clear_all returns False
(matches original — clear failure was non-fatal in cancel_all path)
- Same TERMINAL_STATUSES set: completed/failed/not_found/cancelled/skipped/
already_owned (lifted to module-level constant)
- Same empty-batch pruning + same batch_locks cleanup
- Same lock acquisition pattern (single tasks_lock)
Tests: 14 new under tests/downloads/test_downloads_cancel.py covering
single cancel, cancel-all happy + failure paths, clear-finished + sweep
gate, local task pruning across all 7 active/terminal states, batch
queue trimming, batch_locks cleanup.
Full suite: 921 passing (was 907). Ruff clean.
