feat(editor): add --gen-mesh-chalice ceremonial goblet

82nd procedural mesh primitive. 3-tier ceremonial chalice:

  • foot — wide flat base disc (the goblet's footprint on
    the table)
  • stem — thin tall connecting column (the holding-grip)
  • bowl — wider shallow cup at the top

Validates that stemR < both footR and bowlR so the
silhouette always reads as the classic wide-narrow-wide
goblet shape rather than a degenerate cylinder stack.

Three more primitives that consume the addClosedCylinderY
helper this batch (lantern + chalice from the previous
two commits + this), pattern is now well-established.

Useful for chapel altars, treasure rooms, royal-court
banquet tables, ritual / cult scenes, dwarven mead halls,
fairy-tale storybook props. Watertight under weld
(verified 252 manifold edges, 0 boundary, 0 non-manifold).

Milestone: kArgRequired now reaches 420 documented flags.

tools/editor/cli_help.cpp

@@ -316,6 +316,8 @@ void printUsage(const char* argv0) {
     std::printf("                         Candle: thin wax pillar on optional saucer base (set saucerR=0 to skip) — chapels / vigil scenes\n");
     std::printf("  --gen-mesh-lantern <wom-base> [baseR] [baseH] [globeR] [globeH] [neckR] [neckH] [capR] [capH] [sides]\n");
     std::printf("                         Lantern: 4-tier base + glass-globe + neck + cap stack (hand lantern / oil lamp silhouette)\n");
+    std::printf("  --gen-mesh-chalice <wom-base> [footR] [footH] [stemR] [stemH] [bowlR] [bowlH] [sides]\n");
+    std::printf("                         Chalice: ceremonial 3-tier foot + stem + bowl goblet (chapel / treasure / ritual scene)\n");
     std::printf("  --gen-camp-pack <outDir>\n");
     std::printf("                         Convenience: emit tent + firepit + bedroll + canopy + woodpile + haystack into outDir as 6 .wom files\n");
     std::printf("  --gen-blacksmith-pack <outDir>\n");