fix(render3d): the Vulkan renderer stops leaking as it loads and draws

- every texture upload malloc'd a CPU copy of its pixels and never freed it (236 MB over the
  valley's boot, and again for every model loaded later): the pixels are converted straight
  into the mapped staging buffer
- the per-level and per-layer views gvk_view_of made outlived their texture, and on MoltenVK a
  view keeps its Metal texture alive: a released texture takes its views with it, and the cache
  is keyed by numbers instead of a string built on every call
- the Vulkan structs filled for a draw, pass, barrier, descriptor set, buffer, allocation or
  upload (about sixty call sites) come from a reused 1 MB scratch ring (gvk_tmp)
- the descriptor-set cache and the retired buffers are emptied in place, not replaced; the grass
  cull's dispatch arguments are made once
- macOS drains an autorelease pool each frame (Vk.frame_pool, lvk_frame_pool in vk_mac.ll)
- R3D_VK_PROF reports Vulkan objects made and destroyed by kind, and every cache's length
- examples/rendering/smooth presents through render3d, so it runs on Vulkan too

The full valley on headless Vulkan loads to 2.18 GB and holds (it passed 8 GB while loading
before). ludic-dev test 305/305, selfhost-test 33/33.

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

packages/ludic.render3d/gpu.ludic

@@ -201,7 +201,7 @@ function gpu_query_new(render3d_st: mut Render3dState, n: int, ids: words) -> vo
 function gpu_query_begin(render3d_st: mut Render3dState, id: int) -> void { if render3d_st.gpu_kind == GPU_VK { gvk_query_begin(render3d_st, id);  return };  gl_begin_query(GL_TIME_ELAPSED, id) }
 function gpu_query_end(render3d_st: mut Render3dState) -> void { if render3d_st.gpu_kind == GPU_VK { gvk_query_end(render3d_st);  return };  gl_end_query(GL_TIME_ELAPSED) }
 # true once the query has its result; the nanoseconds (low 32 bits) are then in out[0]
-function gpu_query_result(render3d_st: Render3dState, id: int, out: words) -> bool {
+function gpu_query_result(render3d_st: mut Render3dState, id: int, out: words) -> bool {
   if render3d_st.gpu_kind == GPU_VK { return gvk_query_result(render3d_st, id, out) }
   gl_get_query_objectiv(id, GL_QUERY_RESULT_AVAILABLE, out)
   if out[0] == 0 { return false }