nav, physics: Recast's and Detour's memory counted (nav_heap_bytes / _peak / _allocs, a counted allocator registered at load, tile bytes staged from it); package tests that crossing the map and back holds the native bytes

The user's walk showed the footprint rising outside the Ludic heap. Jolt's bytes were already counted;
the navmesh's were not, so nothing could see them. Now:
- ludic.nav nav_heap_test: fifty crossings of a four-tile map by the resident index hold the tiles in and
  the native bytes to the first crossing's; a thousand crowd walkers in and out grow nothing; a reset
  gives back every byte the mesh took.
- ludic.physics cross_heap_test: a 1 km map of 64 m chunks kept to a ring round a player crossing
  corner to corner and back, each chunk a heightfield, twelve owned posts and six owned scaled hulls
  as the game makes them: six more crossings hold the bodies, the shapes and Jolt's bytes and peak
  exactly. (A post made as an offset of a cylinder, with only the offset owned, leaked the cylinder
  every time: the game's solid_pillar owns its cylinder directly.)

lib/macos-arm64 rebuilt; lib/windows-x64 needs native/build.sh run on the PC for the new exports.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.nav/native/shim/nav_shim.cpp

@@ -7,6 +7,8 @@
 #include <DetourNavMeshQuery.h>
 #include <DetourCommon.h>
 #include <DetourCrowd.h>
+#include <RecastAlloc.h>
+#include <DetourAlloc.h>
 #include <cstring>
 #include <cstdlib>
 #include <cmath>
@@ -18,6 +20,8 @@
 #define NAV_SHIM extern "C" __attribute__((visibility("default")))
 #endif
 
+#include "nav_alloc.inl"
+
 #ifdef _WIN32
 extern "C" __declspec(dllimport) int __stdcall QueryPerformanceCounter(long long *);
 extern "C" __declspec(dllimport) int __stdcall QueryPerformanceFrequency(long long *);