Framework for Sacred 2 Gold, game log mirror, borderless fullscreen

Ported from sacredK with module-relative addresses, hooks by exported
name and a SHA-256 check of the six game modules (Community Patch
2.65.1). Borderless windowed at monitor size replaces exclusive
fullscreen, whose focus loss during loading made the game quit and
crash on exit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/todo.md

@@ -0,0 +1,11 @@
+# Todo
+
+- Engine tick hook calling `re::EngineHeartbeat`, so the hang watchdog
+  (`src/re/crash.cpp`) works.
+- Hooks in modules loaded at runtime (`plugin_*.dll`, `s2logicdll.dll`):
+  resolve them when the module loads (LoadLibrary hook) and add them to the
+  build check.
+- Log levels: find `LogMessageLevel` names and the threshold, so filtered
+  messages can be shown too.
+- Autotest (start, menu clicks, screenshots) as in sacredK, once the menus are
+  known.