HUD: centre the taskbar, move the portrait/health panel to the right edge

New mods/hud: while a HUD window renders, screen-space vertices passed to
D3D7 DrawPrimitive/DrawIndexedPrimitive are shifted by dx; while it handles
an event, the UI event point (category 5, +0x48) is shifted by -dx. Applied
to cUI_Taskbar2 (centred) and cUI_Mercenary (portrait + health, right edge).
3D belt items line up without help (their projection is screen-centred).
re::AttachRuntimeHook hooks functions only known at runtime (COM methods).

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

CMakeLists.txt

@@ -32,6 +32,7 @@ add_library(sacred_re SHARED
     src/game/engine/cmdline.cpp
     src/mods/borderless.cpp
     src/mods/widescreen.cpp
+    src/mods/hud.cpp
 )
 target_include_directories(sacred_re PRIVATE src)
 target_compile_options(sacred_re PRIVATE ${SACRED_RE_CXX_FLAGS})