fix(mister): handle pixel-repeated 1440p framebuffer scaling

[zaparoo-automation-bot]

MiSTer video mode 14 (2560×1440@60) rendered frontend through an incorrect 640×720 framebuffer, stretching the UI horizontally.

Root cause

Mode 14 stores 1280×1440 timing geometry with horizontal pixel repetition (pr=1) to produce physical 2560×1440 output.

Scale-relative fb_cmd handling divided stored horizontal and vertical dimensions uniformly. Frontend’s full-then-half probe therefore produced 640×720.

Main’s normal framebuffer configuration already accounts for pixel repetition by applying different horizontal and vertical scaling.

Expected behavior

• Mode 14 uses a 1280×720 logical framebuffer.
• Physical output remains 2560×1440.
• UI renders at exact 2× scale without horizontal stretching.
• Other pixel-repeated modes follow equivalent logical scaling.
• Non-pixel-repeated 720p, 1080p, and 1440p modes remain unchanged.

Verification

• Confirm framebuffer mode and virtual size are 1280×720.
• Verify correct aspect ratio from frontend launch.
• Verify restart and game-return behavior.
• Cover scale-relative framebuffer geometry with and without pixel repetition.

[asturur]

same as #163

[asturur]

same as #162

[wizzomafizzo]

Fixed in ZaparooProject/Main_MiSTer#15. Live verification on MiSTer mode 14 confirmed /dev/fb0 at 1280×720 with correct aspect ratio on a 2560×1440 display. Wrapper build and deployed binary hashes matched.