fix: resolve font NameError, JPEG/webp mismatch, and duplicate Tower …of Hanoi entry- Load fonts once at top of generate_banner() to fix NameError in matrix branch- Bundle DejaVu Sans Bold font for consistent cross-platform rendering- Warn via RuntimeWarning if no font is found instead of failing silently- Save banners as true WebP instead of JPEG bytes in a .webp file- Remove duplicate Tower of Hanoi entry that silently overwrote its own output#1272