Play Framework

chore: drop play.bak and play.bat.bak (PF-90)

Backups of the Python launcher (play.bak) and its Windows shim
(play.bat.bak) created during the PF-90 migration. The current
play shell wrapper has been in place and tested for several
commits — the safety net is no longer needed and only the
single play script should exist at the repo root.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>