After the CI unification, the PyInstaller / prepare_resources route scripts
were fully orphaned (referenced only by each other and stale docs). Remove the
cluster:
build_backend.py, prepare_resources.py, check_bundle_size.py, smoke_api.py,
build_desktop.py, dev_desktop.py, test_desktop.py, quick_build_check.sh,
build_release.py
scripts/ now holds only what's live: build_macos_arm.sh (the one packaging
route), verify_desktop.sh (backend smoke), monitor_whisper.py (runtime).
Rewrite scripts/README.md and BUILD_GUIDE.md to describe the single PBS route
accurately (they previously documented the dead PyInstaller flow), and fix the
stale build command in RELEASE_CHECKLIST.md.
Also removed a 94M stale _autoclip-backend-pyinstaller-bak left in
src-tauri/resources/ (untracked build junk).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>