ludic.nav (23.5b): a baked mesh resident by chunk

nav_load_index indexes a saved mesh's tiles (cell, offset, size, ref) from their headers and keeps the file open, with no tile in. nav_tiles_keep reads in the tiles within rin of any player and removes those past rout of all; the file is read through Ludic's pack-aware file_open. The file format is unchanged. tiles_test: tiles come and go with the point, a path works across the seams once they are in, and a reset closes all. Measured on the baked maps (the 900 / 1100 m ring round the start): Maroon 617 of 1807 tiles in, 8.9 MB instead of about 27 MB for a person and 5.4 MB of about 14 for a large walker; Lamar 391 of 1147. Both libraries are rebuilt; nav 17/17 on the Mac and the PC, DLL KERNEL32 only.

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

packages/ludic.nav/native/shim/nav_tiles.inl

@@ -103,6 +103,7 @@ NAV_SHIM void *nav_load(const unsigned char *buf, int size) {
 
 // a file read straight into the shim's own memory rather than a Ludic slice (which is never given
 // back): nav_stage hands out the room, nav_load_staged parses it and frees it, whatever the outcome
+NAV_SHIM void nav_unstage(unsigned char *buf) { free(buf); }
 NAV_SHIM unsigned char *nav_stage(int size) { return size > 0 ? static_cast<unsigned char *>(malloc(size)) : nullptr; }
 NAV_SHIM void *nav_load_staged(unsigned char *buf, int size) {
   void *h = buf ? nav_load(buf, size) : nullptr;