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.c

@@ -0,0 +1,51 @@
+#include "version_bridge.h"
+#include "version_host.h"
+#include <string.h>
+
+static uint64_t read64(const void *p) {
+  uint64_t value;
+  memcpy(&value, p, sizeof(value));
+  return value;
+}
+
+u32 w2c_env_read_or_throw(struct w2c_env *env, u64 source, u64 destination, u64 size) {
+  wasm_rt_memory_t *memory = w2c_factorio__version_memory(env->module);
+  if (memory->size < 24 || source > memory->size - 24 ||
+      size > memory->size || destination > memory->size - size) return 2;
+  uint64_t data = read64(memory->data + source);
+  uint64_t length = read64(memory->data + source + 8);
+  uint64_t cursor = read64(memory->data + source + 16);
+  if (data > memory->size || length > memory->size - data) return 2;
+  if (cursor > length || size > length - cursor) return 1;
+  memmove(memory->data + destination, memory->data + data + cursor, (size_t)size);
+  cursor += size;
+  memcpy(memory->data + source + 16, &cursor, sizeof(cursor));
+  ++env->reads;
+  return 0;
+}
+
+int factorio_version_parse(const uint8_t *bytes, size_t length, FactorioMapVersion *out) {
+  if (!bytes || !out) return 2;
+  if (!wasm_rt_is_initialized()) wasm_rt_init();
+  w2c_factorio__version module;
+  struct w2c_env env = {.module = &module};
+  wasm2c_factorio__version_instantiate(&module, &env);
+  uint8_t *memory = w2c_factorio__version_memory(&module)->data;
+  uint64_t registers[32] = {0};
+  registers[0] = 2048; /* guest output object */
+  registers[1] = 512;  /* opaque stream adapter */
+  registers[31] = 65280;
+  uint64_t reader[3] = {4096, length < 9 ? length : 9, 0};
+  memcpy(memory, registers, sizeof(registers));
+  memcpy(memory + 512, reader, sizeof(reader));
+  memcpy(memory + 4096, bytes, (size_t)reader[1]);
+  int result = (int)w2c_factorio__version_run(&module, 0);
+  if (!result) {
+    uint64_t packed = read64(memory + 2048);
+    *out = (FactorioMapVersion){.major = (uint16_t)(packed >> 48),
+      .minor = (uint16_t)(packed >> 32), .patch = (uint16_t)(packed >> 16),
+      .build = (uint16_t)packed, .flag = memory[2056]};
+  }
+  wasm2c_factorio__version_free(&module);
+  return result;
+}