Bones: client-side SetupBones/studiohdr groundwork

- bones.cpp: resolve IClientRenderable via IClientUnknown slot 6, validate it
  against IVModelInfo GetModel, call SetupBones (slot 16) with engine Time()
  (slot 14), and parse the studio header (GetStudiomodel, slot 29) for
  bones/bone names/parents and hitboxes
- cache up to 64 entity bone snapshots, refreshed at ~30 Hz
- helpers: bone_find/parent/pos, hitbox_center (e.g. "head")
- debug probe: HL2H_BONE_DEBUG=1 draws a white marker at each NPC's head
  hitbox center and logs bone count/head position once

1 files changed, 8 insertions, 0 deletions

diff --git a/src/hl2h.h b/src/hl2h.h
index 0986017..d57105d 100644
--- a/src/hl2h.h
+++ b/src/hl2h.h
@@ -168,6 +168,14 @@ void draw_text_col(int x, int y, const char *s, int r, int g, int b);
 void esp_draw();
 bool world_to_screen(const Vector &w, float &sx, float &sy);
 
+// bones.cpp — client-side animated skeleton / hitbox access (see there)
+bool bones_update(int idx, void *ent);
+int bones_count(int idx);
+int bone_find(int idx, const char *name);
+int bone_parent(int idx, int bone);
+bool bone_pos(int idx, int bone, Vector &out);
+bool hitbox_center(int idx, const char *hitbox_name, Vector &out);
+
 void outer_draw();
 // raw ISurface slot calls used by the PaintTraverseEx hook (hl2h.cpp)
 using SurfFn = void (*)(void *, ...);