Rebuild the foliage with leaf cards: leafier silhouette at two thirds the triangles

TODO.md

@@ -945,8 +945,11 @@ scorecard source, this milestone is the actionable list.
 - [ ] Rebuild the ranked prop candidates from §D: the foliage-language P1
       (`planter_box`/`round_planter` foliage, `street_tree`/`palm_tree`), plus the
       `newspaper_box` slot and `bollard` collar if the budget allows.
-- [ ] Replace the flat `_shrub()`/`_tree()` clumps with carded clusters and keep the 60k
-      library triangle budget; measure before/after.
+- [x] Replace the flat `_shrub()` clumps with **leaf cards** (`_leaf_card()`), the foliage-language
+      P1. Each shrub is now one low-poly inner mass wrapped in 18–53 two-triangle cards scattered on
+      the canopy shell and tilted off its normal, so the silhouette is ragged instead of
+      rock-like — and it is *cheaper*: `planter_box` 1,324 → 818 tris, `round_planter`
+      1,240 → 808, `street_tree` 2,592 → 1,506. Props total 13,808 → 11,784 tris (budget 60k).
 - [ ] Review the 18 gear pieces for silhouette and strap/buckle readability and rebuild only what
       fails; re-run `fit` after every change.
 - [ ] Verify prop colliders and navigation obstacles against the final silhouettes.