feat(demo): seed two showcase events, Treasure drop and Payday

The demo default set (org lead, 2026-10-27: curated showcase) puts its
permissions and NPCs on the rig, where the baseline restores them; events
live in the site's database, which every wipe drops, so they belong in the
fixture. Both are manual, published, on the demo server:

- Treasure drop: rust.dt.start, Easy.
- Payday: rust.coins.pay, 500 coins to every linked player, said in chat.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

deploy/demo/seed.json

@@ -58,6 +58,51 @@
           ]
         },
         "publish": true
+      },
+      {
+        "title": "Treasure drop",
+        "summary": "Starts a Dangerous Treasures event: a guarded, burning chest somewhere on the map. Run it from Admin → Events.",
+        "timezone": "UTC",
+        "spec": {
+          "schedule": { "kind": "manual" },
+          "phases": [
+            {
+              "key": "main",
+              "label": "Drop the treasure",
+              "steps": [
+                { "actionId": "rust.dt.start", "params": { "server": "demo", "level": 0 } }
+              ]
+            }
+          ]
+        },
+        "publish": true
+      },
+      {
+        "title": "Payday",
+        "summary": "Pays every linked player 500 coins through Economics. Run it from Admin → Events.",
+        "timezone": "UTC",
+        "spec": {
+          "schedule": { "kind": "manual" },
+          "phases": [
+            {
+              "key": "main",
+              "label": "Pay",
+              "steps": [
+                {
+                  "actionId": "rust.coins.pay",
+                  "params": {
+                    "server": "demo",
+                    "amount": 500,
+                    "recipients": "linked",
+                    "message": "Payday! You received {amount} coins.",
+                    "delivery": "chat"
+                  }
+                }
+              ]
+            }
+          ]
+        },
+        "publish": true
       }
     ]
   },