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/duncarrow.json

@@ -0,0 +1,10 @@
+{
+  "body": "Duncarrow is a walled market town at the edge of the Tallow Reach, grown fat on the road trade between the lowland grain towns and the pass. Timber and wool go out; salt, iron, and coin come in. Ten militia hold the walls under the mayor's charter. It is, by every visible measure, a prosperous and orderly place, which is exactly the reputation its mayor has spent fifteen years building and depends on.",
+  "id": "town.duncarrow",
+  "related": [
+    "region.the-tallow-reach",
+    "place.the-white-antlers",
+    "person.mayor-oswin-crell"
+  ],
+  "type": "town"
+}