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.

docs/research/steam-boundary.md

@@ -0,0 +1,34 @@
+# Steam-free single-player target
+
+User-directed scope: exclude Steam integration; retain basic local gameplay. Steam matchmaking, cloud saves, achievements, rich presence, overlay and Steam networking are outside this port's target. The installed macOS game is not modified.
+
+The current translated RNG library and iOS prototype contain no Steam imports or Steam dynamic dependency. `tools/build_rng.py` rejects Steam undefined symbols; `tools/package_ios.py` checks both imports and linked libraries before packaging.
+
+## Original binary observations
+
+REA Mach-O import inventory observed eleven direct Steam imports, including `SteamAPI_Init`, callbacks, shutdown and SteamInternal interface acquisition. Import coverage is not exhaustive, and virtual interface calls extend beyond these named imports.
+
+Independent LLVM symbol inspection found `SteamContextInterface`, `SteamContext`, and `DummySteamContext`. REA/Hopper subsequently confirmed the factory disassembly and decompilation. The interface factory is at ARM64 VA `0x100267594` (`SteamContextInterface::createContext(bool, bool)`). Its observed branches are:
+
+- Nonzero second argument (`w1`) selects an object referencing `DummySteamContext`'s vtable.
+- With the second argument zero, bit zero of the first argument (`w0`) branches to a base-interface object at `0x100267640`, without entering the Steam initialization block.
+- The other branch contains calls into the Steam path and constructs `SteamContext` if initialization succeeds.
+
+Parameter names and caller-level meaning have not yet been established. These observations do not prove full game startup through either optional context. The correct integration point is the factory/interface boundary, not a blanket success-returning replacement for every Steam import.
+
+REA also found that the Steam initialization stub has two observed callers: the factory and `GlobalContext::init` at `0x100161584`. The latter contains an **inlined** Steam initialization block beginning at `0x100161608`. Editing only the out-of-line factory would miss it. At `0x100161604`, startup branches on `GlobalContext::headlessMode`; headless startup constructs the base context without Steam. The graphical port must select local services independently of headless mode, while preserving graphical startup. Whole-function body ranges and complete indirect-reference classification are unavailable from Hopper's public API, so these observations are not a complete reachability proof.
+
+## Retained REA evidence
+
+Canonical bundle: `evidence/factorio-functions-final.json`, ARM64 slice SHA-256 `2cb4de127b50d54c6c5666acfef2263fae16d11a3361ad39353ecf8a66a4d9c7`.
+
+- Factory dossier: `ev_4ebc9cbefaeb34d2e4f642c8cfa48d5035442aa80f6a438bf6481d215d1fe694`.
+- Steam initialization stub/callers: `ev_c2713194813cae2a2677b7d73a284f9f99b4b9214e59f58cf8ee2a0ffc159f09`.
+- Global startup dossier: `ev_7f2a2b88000ba82d85771c0f368eae9cf0a1f071beb7d73506ba6bbf3c0a22eb`.
+- Base `isSteamApiInitialized()` assembly returns zero: `ev_0b47cba381075942160840ec0d392a8f05803c3c8a2ebb672bb01c4a282f4a5b`.
+
+The interface includes cloud storage, locale, networking, callbacks, on-screen keyboard, stats and achievements. Local replacements must preserve actual method contracts and object layout once lifted callers use them. Returning invented success or a fake Steam identity would hide missing behavior; the port should expose unavailable optional services and use local file storage and native text entry.
+
+## Remaining work
+
+Replace the inlined startup integration when that engine function is lifted, audit optional-service checks, and prove no Steam-only branch is reachable from the chosen local startup. A full translated engine does not exist yet, so Steam exclusion has only been verified for the current prototype.