WASD movement for the player

While W/A/S/D are held, the controlled creature gets a plain walk order every
engine tick toward its position plus the pressed screen direction, as the
mouse does while its button is held (every mouse event re-sends a walk to the
cursor point); releasing sends the target-less stop order of a released mouse
button. W/A/S/D key events are swallowed before the hotkeys see them; their
old actions move to G (action slot 3), V (pick up nearby) and K (save game
window) for now, configurable in [wasd].

docs/wasd.md: order format, measured mouse behaviour, hotkey map.
docs/todo.md: better pathfinder; final bindings for the moved hotkeys.
re::ConfigString for string settings.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/re/config.cpp

@@ -1,6 +1,7 @@
 #include "re/config.h"
 
 #include <cstring>
+#include <iterator>
 
 #include <windows.h>
 
@@ -34,4 +35,16 @@ int ConfigInt(const char* section, const char* key, int fallback) {
     return static_cast<int>(GetPrivateProfileIntW(Widen(section).c_str(), Widen(key).c_str(), fallback, g_path.c_str()));
 }
 
+std::string ConfigString(const char* section, const char* key, const char* fallback) {
+    if (g_path.empty()) {
+        return fallback;
+    }
+    wchar_t value[256];
+    GetPrivateProfileStringW(Widen(section).c_str(), Widen(key).c_str(), Widen(fallback).c_str(), value,
+                             static_cast<DWORD>(std::size(value)), g_path.c_str());
+    char narrow[256];
+    WideCharToMultiByte(CP_UTF8, 0, value, -1, narrow, sizeof(narrow), nullptr, nullptr);
+    return narrow;
+}
+
 } // namespace re