feat: wild family complete — cave, mountain, river, lake, valley theme packs

Five wild-kernel themes, each 4 motifs:
  cave      dark · deep · echo · keeping        (cave geometry)
  mountain  ascent · cold · pass · weight       (cave)
  river     crossing · current · course · drowned  (fen)
  lake      stillness · mirror · sunken · rising   (fen)
  valley    ridges · shelter · bottom · weather (forest)

Two rendering fixes surfaced by the new claimants, both in skeleton.mjs:
  - `{conscript}'s` rendered "the climbers's"; conscripts are plural noun
    phrases, so fill() now collapses s's to s'.
  - claimants carrying their own article rendered "The The Grey"; named()
    only prefixes when one is absent.

All 16 themes validate; 39 tests pass. Module → 0.6.0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

foundry-module/module.json

@@ -2,7 +2,7 @@
   "id": "vanity-delve",
   "title": "DELVE — a dungeon layer for VANITY",
   "description": "Generates a coherent delve and sequences VANITY's Forge to stage it, one area at a time.",
-  "version": "0.5.0",
+  "version": "0.6.0",
   "compatibility": {
     "minimum": "13",
     "verified": "14.365"