fix(player): suppress stale chunk logs after disconnect

[balloob-travel]

Summary

• stop logging stale player chunk drops once the client transport is already disconnected
• rename the remaining debug message so it describes stale delivery without an active stream
• cover both connected and disconnected stale-chunk cases in player role tests

Testing

• ./scripts/run-in-env.sh pytest tests/server/roles/test_player_v1.py -q
• ./scripts/run-in-env.sh pytest tests/server/test_push_stream_behavior.py -q
• ./scripts/run-in-env.sh pytest tests/server/test_sendspin_client_persistence.py -q
• ./scripts/run-in-env.sh ruff check aiosendspin/server/roles/player/v1.py tests/server/roles/test_player_v1.py

Closes #185