docs: require hygiene budgets on every showcase piece

Copied mesh-hygiene-audit combinatorics, grounded zmin, and BVH contact gaps are now conventions so the next visual pass inherits them.

Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: TMHSDigital

docs/gallery/index.html

@@ -1052,12 +1052,12 @@ <h2><a href="water-trough/">water-trough</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="hitching-post/" aria-label="hitching-post example detail page">
-          <img src="assets/hitching-post-hero.webp" alt="hitching-post — A procedural hitching post through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract." loading="lazy" decoding="async" />
+          <img src="assets/hitching-post-hero.webp" alt="hitching-post — A procedural hitching post (corner-aligned cap, stub-and-tenon arm, collar shoe, eye-threaded rings) through UVs, bake, LOD, collider, and Unity glTF…" loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="hitching-post/">hitching-post</a></h2>
-          <p class="teaches">A procedural hitching post through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
-          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 848 tris, two materials with 262 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.460×0.194×1.260 m, LOD ratios in band (5.2 COLLAPSE more aggressive on LOD2), convex collider 144 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.</p>
+          <p class="teaches">A procedural hitching post (corner-aligned cap, stub-and-tenon arm, collar shoe, eye-threaded rings) through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 1598 tris, two materials with 269 wood and 532 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.460×0.191×1.258 m, zmin 0, hygiene 0, wood-metal BVH gap 0.45 mm, LOD ratios in band, convex collider 78 tris, non-empty glTF. --skip-decimate exits 9 on LOD1; --lift-z exits 16 on grounded zmin.</p>
           <a class="card-link" href="hitching-post/">View example <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>
@@ -1162,12 +1162,12 @@ <h2><a href="wooden-ladder/">wooden-ladder</a></h2>
       </article>
       <article class="card" data-tags="mesh export showcase">
         <a class="card-media" href="hay-bale/" aria-label="hay-bale example detail page">
-          <img src="assets/hay-bale-hero.webp" alt="hay-bale — A procedural bound hay bale with a bevelled loaf, end nap, and two sisal twine belts through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed…" loading="lazy" decoding="async" />
+          <img src="assets/hay-bale-hero.webp" alt="hay-bale — A procedural bound hay bale with a cinched pillow loaf, end nap, and two sisal twine belts through UVs, bake, LOD, collider, and Unity glTF, asserting…" loading="lazy" decoding="async" />
         </a>
         <div class="card-body">
           <h2><a href="hay-bale/">hay-bale</a></h2>
-          <p class="teaches">A procedural bound hay bale with a bevelled loaf, end nap, and two sisal twine belts through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
-          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 252 tris, two materials with 66 hay and 60 twine faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.916×0.520×0.401 m, LOD ratios in band (5.2 COLLAPSE more aggressive), convex collider 68 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.</p>
+          <p class="teaches">A procedural bound hay bale with a cinched pillow loaf, end nap, and two sisal twine belts through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.</p>
+          <p class="witnesses"><span class="tag">witnesses</span> Recomputed: 852 tris, two materials with 294 hay and 132 twine faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.920×0.517×0.426 m, zmin 0, hygiene 0, hay-twine BVH gap 0.07 mm, LOD ratios in band, convex collider 78 tris, non-empty glTF. --skip-decimate exits 9 on LOD1; --lift-z exits 16 on grounded zmin.</p>
           <a class="card-link" href="hay-bale/">View example <span aria-hidden="true">&rarr;</span></a>
         </div>
       </article>

showcase/README.md

@@ -33,7 +33,16 @@ entry in `showcase/gallery.json`, and a rendered still.
   assigned `DECLARED` is not a check).
 - **Falsifier** breaks one pipeline stage so a **named** budget fails and
   the piece exits its documented code. Prove default and falsifier on
-  4.5.11, 5.1.2, and 5.2.1.
+  4.5.11, 5.1.2, and 5.2.1. `--skip-decimate` is the LOD-ratio
+  falsifier (exit 9). `--lift-z` is the grounded-zmin falsifier (exit 16).
+- **Hygiene budgets.** Copied combinatorics from
+  `examples/mesh-hygiene-audit` (do not import the example). Every piece
+  asserts on the generated mesh: non-manifold edges 0, loose verts 0,
+  loose edges 0, doubles at 1e-5 0, zero-area faces 0, n-gons 0, world
+  AABB min Z within 1e-4 of 0. Multi-body props do **not** require Euler
+  characteristic 2 — that is a single-shell contract. Pairs of parts
+  meant to touch assert a BVH surface gap below a named epsilon
+  (vert-vert is the wrong metric for thin straps and collars).
 - **Exit codes** are file-local: `0` success, argparse `2`, `3` and above
   in check order. `9` is legal. FATAL `sys.exit(1)` is a crash, never a
   named check.

showcase/gallery.json

@@ -188,8 +188,8 @@
     {
       "name": "hitching-post",
       "dir": "showcase/hitching-post",
-      "teaches": "A procedural hitching post through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "witnessesFix": "Recomputed: 848 tris, two materials with 262 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.460×0.194×1.260 m, LOD ratios in band (5.2 COLLAPSE more aggressive on LOD2), convex collider 144 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.",
+      "teaches": "A procedural hitching post (corner-aligned cap, stub-and-tenon arm, collar shoe, eye-threaded rings) through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
+      "witnessesFix": "Recomputed: 1598 tris, two materials with 269 wood and 532 metal faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.460×0.191×1.258 m, zmin 0, hygiene 0, wood-metal BVH gap 0.45 mm, LOD ratios in band, convex collider 78 tris, non-empty glTF. --skip-decimate exits 9 on LOD1; --lift-z exits 16 on grounded zmin.",
       "hero": "docs/gallery/assets/hitching-post-hero.webp",
       "preview": "showcase/hitching-post/preview.webp",
       "tags": [
@@ -308,8 +308,8 @@
     {
       "name": "hay-bale",
       "dir": "showcase/hay-bale",
-      "teaches": "A procedural bound hay bale with a bevelled loaf, end nap, and two sisal twine belts through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "witnessesFix": "Recomputed: 252 tris, two materials with 66 hay and 60 twine faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.916×0.520×0.401 m, LOD ratios in band (5.2 COLLAPSE more aggressive), convex collider 68 tris, non-empty glTF. --skip-decimate exits 9 on the LOD1 ratio budget.",
+      "teaches": "A procedural bound hay bale with a cinched pillow loaf, end nap, and two sisal twine belts through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
+      "witnessesFix": "Recomputed: 852 tris, two materials with 294 hay and 132 twine faces, UVs in 0..1 with zero AABB overlap, outer AABB 0.920×0.517×0.426 m, zmin 0, hygiene 0, hay-twine BVH gap 0.07 mm, LOD ratios in band, convex collider 78 tris, non-empty glTF. --skip-decimate exits 9 on LOD1; --lift-z exits 16 on grounded zmin.",
       "hero": "docs/gallery/assets/hay-bale-hero.webp",
       "preview": "showcase/hay-bale/preview.webp",
       "tags": [