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.

runtime/version_bridge.h

@@ -0,0 +1,13 @@
+#ifndef FACTORIO_VERSION_BRIDGE_H
+#define FACTORIO_VERSION_BRIDGE_H
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct {
+  uint16_t major, minor, patch, build;
+  uint8_t flag; /* Stored byte; semantics have not yet been recovered. */
+} FactorioMapVersion;
+
+/* 0=success; 1=short header; 2=invalid memory. Parses only the version header. */
+int factorio_version_parse(const uint8_t *bytes, size_t length, FactorioMapVersion *out);
+#endif