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/env.ludic

@@ -189,6 +189,9 @@ export state Render3dState {
   gvk_pool: long = 0
   gvk_fence: bytes = null
   gvk_frame_fence: bytes = null     # the presented frame still on the GPU (one frame in flight)
+  gvk_tmp_buf: pointer = null        # the per-call scratch ring (gvk_tmp)
+  gvk_tmp_off: int = 0
+  gvk_seen: words = null             # gvk_draw's vertex buffers already bound, reused
   gvk_frame_pending: bool = false
   gvk_frame_pending_cb: pointer = null
   gvk_frame_pending_no: int = -1    # which frame it is (gvk_frame_no when it was submitted)
@@ -197,6 +200,20 @@ export state Render3dState {
   gvk_retired_frame: []int = null   # the last frame that read each retired buffer
   gvk_labels: bool = false          # R3D_VK_LABELS: each profiled pass is a debug label (Metal System Trace)
   gvk_inflight: int = -1
+  gvk_nopool: bool = false
+  # R3D_VK_PROF: Vulkan objects made and destroyed, reported every 120 frames
+  gvk_mk_img: int = 0
+  gvk_mk_view: int = 0
+  gvk_mk_buf: int = 0
+  gvk_mk_mem: int = 0
+  gvk_mk_smp: int = 0
+  gvk_mk_set: int = 0
+  gvk_mk_cmd: int = 0
+  gvk_mk_dpool: int = 0
+  gvk_mk_x_img: int = 0
+  gvk_mk_x_view: int = 0
+  gvk_mk_x_buf: int = 0
+  gvk_mk_x_mem: int = 0
   gvk_label_depth: int = 0            # -1 until asked: 1 leaves the presented frame in flight
   gvk_has_hqr: bool = false
   gvk_ts_period: float = 0.0             # float bits: nanoseconds per timestamp tick
@@ -269,8 +286,9 @@ export state Render3dState {
   gvk_screen_depth: int = 0
   gvk_screen_w: int = 0
   gvk_screen_h: int = 0
-  gvk_layer_views: []string = null  # "tex:layer" -> index into gvk_layer_view
+  gvk_layer_views: []int = null     # generation * 4096 + layer, beside gvk_layer_view_tex
   gvk_layer_view: []long = null
+  gvk_layer_view_tex: []int = null   # the texture each cached view is of, so a release drops them
   gvk_fb_ncolor: words = null       # per framebuffer: colour slots drawn (draw buffers; 0 = none)
   gvk_hdr_want: bool = false        # r3d_hdr: the setting
   gvk_hdr_on: bool = false          # the swapchain is HDR10 now
@@ -377,6 +395,11 @@ export state Render3dState {
   gg_mesh: []Mesh = null
   gg_n: int = 0
   gg_max: int = 0
+  gg_rb: words = null                # the per-frame dispatch arguments, made once (grass_gpu.ludic)
+  gg_cb: words = null
+  gg_bufs: words = null
+  gg_texs: words = null
+  gg_pr: words = null
   grass_band_mesh: []Mesh = null     # per band: the blade it draws (rows fall with distance)
   grass_mesh3: Mesh = null           # three rows: the middle distance
   grass_mesh2: Mesh = null           # two rows, one quad: far enough that the arch is under a pixel