Fix audit findings: crash safety, correctness, rendering, performance

Crash/UB:
- gate every hook behind an init-stage flag until config/surface/input are ready
- publish module maps as immutable atomic snapshots instead of reallocating
  shared vectors under unlocked readers
- validate the %ebp walk in the RandomSeed/RandomFloat hooks against the stack
- bounds-check every RecvTable/RecvProp/string dereference with module_range()
- preserve the Itanium vtable header when cloning (client, CInput, model render,
  studio render)
- reject negative usercmd sequence numbers; guard config_load against a null
  section target; cap the bone parent walk; check mprotect; drop PROT_EXEC on
  the GOT patch; absorb server.so .bss tail

Correctness:
- filter dormant entities across ESP, aimbot, triggerbot, melee, items and
  projectiles (slot self-tested against the local player)
- reset the server-health latch per map and only latch on valid model indices
- bone cache sized for the 128-target scan; set valid=false on every failure;
  head_position keeps searching past an invalid bone
- vischeck steps past glass by probing until clear, and ignores entities owned
  by the target (held weapons, bone followers)
- aimbot: maxs no longer disables it, AABB-aware FOV prefilter, lock hysteresis,
  lead point re-checked for FOV and visibility
- spread: seed hook arms on the no-spread toggle alone; engine toggle only
  controls the RandomFloat zeroing
- resolve m_hOwnerEntity/m_hOwner; NPC lead velocity from the server entity
- vector_angles pitch range, point_ground normal test, underwater jump+duck no
  longer skips combat, semi-auto press/release edge for synthetic fire
- item/projectile markers and blast rings refresh origin per frame while
  discovery stays at 10 Hz; trajectory uses the real m_DmgRadius and honours
  the blast-radius toggle

Rendering/GUI:
- one overlay draw per engine frame (FRAME_RENDER_START boundary), fixing
  alpha stacking and the speed-graph flicker
- clipped lines/outlines and ellipsised text instead of drawing past the
  content pane or shifting over neighbours
- dropdown dismissal consumes the click; hover ignores hidden controls
- chams: reset AlphaModulate, reference shared materials once, restore prop
  tint colour; fonts created once per handle
- projection uses Source's 4:3 aspect scaling and roll; screen size refreshed
  each frame; FOV circle gated on the aim toggles, not the bind

Performance:
- TTL caches for NPC relation, friendly/neutral and damage class
- model names memoised per model index
- entity pointer -> index cache for the triggerbot (was a 4096-slot walk/tick)

Build:
- real Makefile with -MMD dependency tracking, debug/release objects and an
  always-relink rule; build.sh kept as a thin wrapper

1 files changed, 62 insertions, 0 deletions

diff --git a/src/overlay.h b/src/overlay.h
new file mode 100644
index 0000000..6cf86c9
--- /dev/null
+++ b/src/overlay.h
@@ -0,0 +1,62 @@
+#ifndef HL2H_OVERLAY_H
+#define HL2H_OVERLAY_H
+
+#include <cstdint>
+
+// VGUI_Surface030 vtable slots, confirmed against the shipped
+// vguimatsurface.so. This header is the only place that knows them; every
+// consumer goes through the functions below.
+enum SurfaceSlot {
+  SURF_GetEmbeddedPanel = 6,
+  SURF_PushMakeCurrent = 8,
+  SURF_PopMakeCurrent = 9,
+  SURF_DrawSetColor = 10,
+  SURF_DrawFilledRect = 12,
+  SURF_DrawOutlinedRect = 14,
+  SURF_DrawLine = 15,
+  SURF_DrawSetTextFont = 17,
+  SURF_DrawSetTextColor = 18,
+  SURF_DrawSetTextPos = 20,
+  SURF_DrawPrintText = 22,
+  SURF_GetScreenSize = 38,
+  SURF_CreateFont = 66,
+  SURF_AddGlyphSetToFont = 67,
+  SURF_GetTextSize = 75
+};
+
+using HFont = unsigned long;
+
+struct ISurface;
+
+// Set once by install_menu(); every wrapper below is a no-op while it is null.
+extern ISurface *g_surface;
+
+void overlay_color(int r, int g, int b, int a);
+void overlay_fill(int x0, int y0, int x1, int y1);
+void overlay_outline_rect(int x0, int y0, int x1, int y1);
+void overlay_line(int x0, int y0, int x1, int y1);
+void overlay_text_font(HFont f);
+void overlay_text_color(int r, int g, int b, int a);
+void overlay_text_pos(int x, int y);
+void overlay_print_text(const wchar_t *text, int count, int draw_type = 0);
+HFont overlay_create_font();
+bool overlay_add_glyph_set(HFont f, const char *name, int tall, int weight,
+                           int blur, int scanlines, int flags, int range_min,
+                           int range_max);
+void overlay_screen_size(int &w, int &h);
+void overlay_text_size(HFont f, const wchar_t *text, int &w, int &h);
+int overlay_embedded_panel();
+void overlay_push_make_current(int panel, bool use_insets);
+void overlay_pop_make_current(int panel);
+
+// Per-frame draw budget. The engine calls PaintTraverseEx for every panel, and
+// DrawPrintText for every text draw, so the overlay must be collapsed to one
+// draw per frame. A timer cannot do that: panels spaced a few ms apart in the
+// same frame would draw twice and double the alpha of translucent elements.
+// overlay_frame_mark() is called from FRAME_RENDER_START, which is the real
+// frame boundary; if that stops arriving (menu/pause) a 10 ms fallback keeps
+// the GUI repainting.
+void overlay_frame_mark();
+bool overlay_should_draw();
+
+#endif