Native iPhone port of Factorio 2.0.77

Run the original macOS ARM64 game code on iOS:
- tools/retarget.py: header-only Mach-O retargeting to an iOS dylib
- platform/native: UIKit host and macOS API shims (AppKit for SDL's
  Cocoa backend, CoreGraphics displays, CoreAudio device, Metal device
  properties, Wuffs PNG decoding, Steam and peripheral stubs)
- touch, overlay, iOS keyboard and hardware keyboard input
- tools/build_native.py: build, sign, install, data copy, launch
- docs: build guide, controls, architecture

Also includes the earlier static-translation research (ARM64 -> WASM ->
native) under docs/research, runtime/, tests/ and tools/.

No game files are included; the build reads them from a local install.

tools/make_icon.m

@@ -0,0 +1,35 @@
+// Builds the 1024x1024 iOS app icon from the game's own 128 px icon (read from the local install).
+// The gear is scaled with high-quality interpolation onto an opaque dark background
+// (iOS app icons must be opaque).
+// Usage: make_icon SOURCE_PNG OUTPUT_PNG
+#import <Foundation/Foundation.h>
+#import <CoreGraphics/CoreGraphics.h>
+#import <ImageIO/ImageIO.h>
+
+int main(int argc, char **argv) {
+    @autoreleasepool {
+        if (argc != 3) { fprintf(stderr, "usage: make_icon SOURCE_PNG OUTPUT_PNG\n"); return 2; }
+        CGImageSourceRef src = CGImageSourceCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:@(argv[1])], NULL);
+        CGImageRef gear = src ? CGImageSourceCreateImageAtIndex(src, 0, NULL) : NULL;
+        if (!gear) { fprintf(stderr, "cannot read %s\n", argv[1]); return 1; }
+        const size_t size = 1024;
+        CGColorSpaceRef rgb = CGColorSpaceCreateWithName(kCGColorSpaceSRGB);
+        CGContextRef ctx = CGBitmapContextCreate(NULL, size, size, 8, 0, rgb, (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
+        // Dark warm gradient, close to Factorio's menu backdrop.
+        CGFloat stops[] = {0.20, 0.17, 0.14, 1, 0.07, 0.06, 0.05, 1};
+        CGGradientRef gradient = CGGradientCreateWithColorComponents(rgb, stops, NULL, 2);
+        CGContextDrawRadialGradient(ctx, gradient, CGPointMake(size / 2.0, size * 0.55), 0,
+                                    CGPointMake(size / 2.0, size / 2.0), size * 0.75, kCGGradientDrawsAfterEndLocation);
+        CGContextSetInterpolationQuality(ctx, kCGInterpolationHigh);
+        CGFloat inset = size * 0.12;
+        CGContextDrawImage(ctx, CGRectMake(inset, inset, size - 2 * inset, size - 2 * inset), gear);
+        CGImageRef icon = CGBitmapContextCreateImage(ctx);
+        CGImageDestinationRef dst = CGImageDestinationCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:@(argv[2])],
+                                                                    CFSTR("public.png"), 1, NULL);
+        CGImageDestinationAddImage(dst, icon, NULL);
+        BOOL ok = CGImageDestinationFinalize(dst);
+        CFRelease(dst); CGImageRelease(icon); CGGradientRelease(gradient); CGContextRelease(ctx);
+        CGColorSpaceRelease(rgb); CGImageRelease(gear); CFRelease(src);
+        return ok ? 0 : 1;
+    }
+}