Replaces the auto-reassign-to-shorter-game logic (which fired while the
current game was still in progress) with a strict workflow:
1. Check if assigned game is finished.
2. If not, do nothing.
3. If yes, pick the next shortest game and prompt the user.
4. If the user skips, ignore that game for 7 days and pick the next
shortest candidate.
Changes:
- State: add skipped_until + skip_for_days + active_skipped_ids.
- scanning.pick_next_game: optional on_select callback drives a
sequential picker that filters skipped IDs; legacy cmd_pick flow
preserved when on_select is None.
- _cmd_done._finalize_completion: pick + prompt via on_select.
- _cmd_done: remove _try_reassign_shorter_game and helpers
(_apply_cached_confidence_to_games, _should_reassign_candidate,
_echo_reassign_decision, _evaluate_reassign_iteration) plus call
site in cmd_done.
- Tests: drop obsolete _try_reassign_shorter_game suite; add
TestPromptKeepOrSkip, TestPickNextGameSequential, and State
skipped_until tests.
