feat(content): promote Duncarrow; build client/server artifacts

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HuHRPE7VfppUJEaoGBEUqZ

content/world/canon/the-tallow-reach.json

@@ -0,0 +1,6 @@
+{
+  "body": "The Tallow Reach \u2014 the lowland march of grain towns and wool roads that Duncarrow sits at the edge of, feeding the pass trade.",
+  "id": "region.the-tallow-reach",
+  "related": [],
+  "type": "region"
+}