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/core/skeleton.mjs

@@ -22,7 +22,13 @@
 import { arcRole } from './director.mjs';
 
 /** Fills {conscript}-style slots. */
-const fill = (tpl, vars) => tpl.replace(/\{(\w+)\}/g, (_, k) => vars[k] ?? `{${k}}`);
+const fill = (tpl, vars) => tpl.replace(/\{(\w+)\}/g, (_, k) => vars[k] ?? `{${k}}`)
+  // Conscripts are plural noun phrases ("the climbers"), so a template's `{conscript}'s`
+  // renders "the climbers's". English takes a bare apostrophe on a plural already ending in s.
+  .replace(/s's\b/g, "s'");
+
+/** Claimants may already carry their own article — "The Grey" must not become "The The Grey". */
+const named = c => (/^(the|a|an) /i.test(c) ? c : `The ${c}`);
 
 /** Facet order used when a facet is exhausted — borrow from a neighbour before repeating. */
 const FACET_ORDER = ['institution', 'ritual', 'demand', 'wound', 'anchor'];
@@ -62,12 +68,12 @@ export function generateSkeleton({ pack, areas = 6, ending = 'authored', rng })
   const prize = { kind: appetite.prize, ...(pack.prizes?.[appetite.prize] ?? {}) };
 
   const transgression =
-    `The ${claimant} ${fill(accommodation.text, { conscript: appetite.conscript })}, ` +
+    `${named(claimant)} ${fill(accommodation.text, { conscript: appetite.conscript })}, ` +
     `so that ${appetite.purpose}.`;
   // The bottom problem is the claimant itself — a person in a tomb, an office in a town.
 
   const bottomProblem = {
-    label: `The ${claimant}`,
+    label: named(claimant),
     wantNow: appetite.want,
     failureState: `is ${appetite.lack} now, and cannot bear it`,
     handledBy: 'giving them what they want, at a price',