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.

platform/native/shim/fx.h

@@ -0,0 +1,43 @@
+// Shared declarations for the macOS-API shims used by the retargeted Factorio binary.
+#pragma once
+#include <CoreGraphics/CoreGraphics.h>
+#include <stdint.h>
+
+#define FX_DISPLAY_ID 1u
+#define FX_EXPORT __attribute__((visibility("default")))
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+FX_EXPORT void fx_log(const char *format, ...) __attribute__((format(printf, 1, 2)));
+FX_EXPORT CGSize fx_screen_points(void);
+FX_EXPORT double fx_screen_scale(void);
+FX_EXPORT double fx_render_divisor(void);
+FX_EXPORT double fx_game_per_uikit(void);
+#ifdef __OBJC__
+FX_EXPORT void fx_main_sync(void (^block)(void));
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+#ifdef __OBJC__
+#import <Foundation/Foundation.h>
+// Selectors sent to Factorio's own SDL classes (declared so ARC accepts the sends).
+@protocol FXAppKitCallbacks
+@optional
+- (void)mouseDown:(id)e; - (void)mouseUp:(id)e; - (void)mouseDragged:(id)e; - (void)mouseMoved:(id)e;
+- (void)rightMouseDown:(id)e; - (void)rightMouseUp:(id)e; - (void)rightMouseDragged:(id)e;
+- (void)otherMouseDown:(id)e; - (void)otherMouseUp:(id)e; - (void)otherMouseDragged:(id)e;
+- (void)scrollWheel:(id)e; - (void)keyDown:(id)e; - (void)keyUp:(id)e; - (void)flagsChanged:(id)e;
+- (void)mouseEntered:(id)e; - (void)mouseExited:(id)e;
+- (void)touchesBeganWithEvent:(id)e; - (void)touchesMovedWithEvent:(id)e;
+- (void)touchesEndedWithEvent:(id)e; - (void)touchesCancelledWithEvent:(id)e;
+- (void)windowDidBecomeKey:(NSNotification *)n; - (void)windowDidResignKey:(NSNotification *)n;
+- (void)applicationDidFinishLaunching:(NSNotification *)n;
+- (NSInteger)tag;
+- (void)insertText:(id)text replacementRange:(NSRange)range;
+@end
+@interface NSObject (FXAppKitCallbacks) <FXAppKitCallbacks>
+@end
+#endif