AmiXcom 0.2.0 alpha

Second alpha. Geoscape went from ~5 fps to ~40 fps on an 040/40-class machine (no JIT), still with the whole screen redrawn every frame. Made with Claude Code.

Changes:

• globe repaints only when something actually changed (rotation, zoom, sun moving the terminator, radar circles); an idle globe costs only the blinking markers
• day/night shadow computed in fixed point instead of ROM soft-float doubles (~280 ms -> ~20 ms per repaint)
• colorkey blits: 4-pixels-at-a-time compare + per-surface span cache - transparent pixels cost nothing
• removed a forced 20 ms sleep the engine took every frame (SDL_Delay(1) rounded up to a full Amiga clock tick)
• new "Amiga" options tab (first tab): Amiga screen title bar on/off, mouse pointer original / Amiga-only; both ON by default
• with the bar on, the screen opens taller (320x211) so the full 320x200 game area stays visible and mouse coordinates map 1:1
• screen bar title comes from the game (name + version from one source)
• Workbench icons included; the tool icons carry the 1 MB stack the game needs
• FPS counter on by default (top-left; measurement aid while the port is optimised)

Still true from 0.1.0: complete alpha, no guarantee a full game plays through; no sound; keyboard text entry broken (mouse works); needs a lot of fast RAM (256 MB tested, 32 MB does not load); AGA only (RTG build included, untested); saving a game takes ~1 min. No X-COM game data included - copy your PC game folders into data/UFO/ and/or data/TFTD/ (see README).