feat(content): POC deserter origin + world fixtures with id-resolution check

content/origins/deserter.json

@@ -0,0 +1,25 @@
+{
+  "schema_version": 1,
+  "id": "deserter",
+  "display_name": "The Deserter",
+  "description": "You walked away from a company that doesn't allow walking away. Greywater was just far enough. You hoped.",
+  "start_location_id": "greywater_docks",
+  "situation": [
+    "Arrived at Greywater by barge before dawn, hood up",
+    "Down to your last coin and owed a favour you can't repay"
+  ],
+  "opening_facts": [
+    "the player deserted the Iron Kettle mercenary company",
+    "a bounty notice for the player circulates in the northern towns"
+  ],
+  "disposition_overrides": { "brannoc_thane": 40, "cadwyn_vell": 15 },
+  "inventory_grants": [
+    { "item_id": "worn_shortsword", "qty": 1 },
+    { "item_id": "coin", "qty": 3 }
+  ],
+  "start_quest_id": "find_the_ledger",
+  "build_constraints": {
+    "allowed_classes": ["sellsword", "assassin", "priest"],
+    "luck_modifier": 0
+  }
+}