v1.9.0 - Experimental adaptive widescreen

This release replaces SMB's old widescreen implementation with a custom renderer and extended level cache. The option is labeled Widescreen (Experimental) in the launcher's Mods screen.

• Adaptive Fit window, 16:9, 21:9, and 32:9, with centered or edge-aligned HUD.
• Ordinary enemies, Piranha Plants, and independent moving platforms load across the widened view.
• Choose Preserve original 4:3 activation or Move when loaded in the wide view.
• Fixes boundary color changes, split enemy/platform sprites, misplaced Goomba groups, missing plants, and the goal flag carrying into 1-2.
• Stock play retains the original renderer. Widescreen remains default-off in the standard packages.

Downloads:

Download	Initial setting
SuperMarioBrosRecomp-windows-x64.zip	Stock; enable widescreen in Mods
SuperMarioBrosRecomp-widescreen-windows-x64.zip	Widescreen 16:9; enemies move on load
SuperMarioBrosRecomp-linux-1.9.0-x86_64.AppImage	Stock; enable widescreen in Mods

The Windows widescreen preset now uses a portable Mods selection. The old widescreen.ini and arbitrary-margin syntax are retired. SHA256SUMS.txt contains checksums for all three downloads. No game ROMs or derived owner-ROM assets are included.

Experimental limits: linked balance platforms, bosses, frenzy controllers, power-ups, and projectiles still have native limits. Player interactions still use the original five enemy slots. Whole-stage viewing/simulation is not included, and every world has not been validated. Experimental mod savestates may be incompatible with earlier builds. See WIDESCREEN.md for details.

Validation: production Windows packages retain all 120 stock route frame hashes; Linux AppImage stock and widescreen runs match all 120 corresponding Windows hashes and screenshots. Targeted checks cover sprite boundaries, plant visibility, flag transitions, lift movement/riding, activation policies, and deterministic save/load.