Initial commit — leak-hunt project complete

Five bugs identified and patched in retail Asheron's Call client:
- v3b: palette refcount over-increment (3-byte NOP at two sites)
- v5: RenderSurface PurgeResource no-op stub (vtable slot 2 thunk)
- v11: two dangling-pointer crash guards (NULL-check + reorder)
- v14: CEnvCell::Destroy ClipPlaneList leak (18-byte JMP to cleanup thunk)
- v22: unpacker stale-pointer SEH guard (whole-function __try/__except)

All five ship in leakfix.dll (117 KB, SHA d282f23c…) which is loaded
by acclient.exe at process start via PE import table patching by
tools/install_leakfix.py.

Controlled 15-client fleet soak: unpatched control died at 26h with
palette exhaustion; all 14 patched clients survived past that point
and reached ≥5-day uptime.

Residual ~15 MB/h growth traced to d3d9.dll's internal slab allocator
(260KB surface backing buffers retained after Release). See REPORT.md
§10 for the full investigation; conclusion is that it's unfixable from
outside d3d9.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

dll/leakfix/stable/src.iter3/thunks.h

@@ -0,0 +1,15 @@
+// thunks.h — replacement functions called by patched code paths
+#pragma once
+
+extern "C" {
+
+// v5 replacement vtable slot 2 functions. __thiscall so vtable call ABI matches.
+int __fastcall purge_rendersurface_thunk(void* self, void* /*edx_unused*/);
+int __fastcall purge_rendertexture_thunk(void* self, void* /*edx_unused*/);
+
+// v14 — naked thunk JMPed to from 0x0052E661.
+// Saves regs, frees inner ClipPlaneList, frees outer wrapper, clears the
+// back-pointer at [esi+0xDC], restores regs, jumps to V14_RESUME_VA.
+void v14_clipplane_cleanup_thunk();
+
+} // extern "C"