v0.2.9 - cleaner Windows kit, Godot scripts and guide (source only)

Source-only Windows kit. No game, no binary. Cleaner BUILD-DQ9.bat (ROM prompt, Python discovery, EU save chip, step output, progress bar), new BUILD-GODOT.bat/PLAY-GODOT.bat and docs/USING_GODOT.md. CI exercises the new entry points ROM-free. The Windows Godot build and a game run on Windows are not yet verified. See CHANGELOG.md.