feat(rust): Guarded Crate — feed, map, Warden, Place a guarded crate (PLAN_REDESIGNS §14.3.5)

Stage 6 of the §14.3 integration plan, on protocol 14. Spec: docs
rust-link/PROTOCOL.md §20.9.

- gc.started and gc.ended public, gc.failed staff's; guardedCrate.js reads
  each row per viewer (the clearer's name for the presence audience, Steam id,
  position and key for staff, `won` for everyone).
- Triggers rust.gc.started and rust.gc.ended (a crate a player cleared only).
- The step rust.gc.place: an event from rust.options.gc_events and a world
  call's location; refused at verify for Guarded Crate absent, NpcSpawn missing
  (D364), console unavailable, or an unknown event. Kept (D373); the run log's
  success line says so (D380). Budget rust.gc.crates.
- Warden (D375): guarded_won, title category guardedwon, Crates cleared column.
- Map marker, server settings line, swagger, engagement manifest, bundle, README.

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

engagement-triggers.json

@@ -698,6 +698,142 @@
         }
       ]
     },
+    {
+      "id": "rust.gc.ended",
+      "label": "A guarded crate was cleared",
+      "description": "A player killed the last guard of a guarded crate on a server.",
+      "kind": "event",
+      "subjectKey": "subject",
+      "audience": "subscribers",
+      "ceiling": "everyone",
+      "version": 1,
+      "variables": [
+        {
+          "name": "serverId",
+          "type": "string",
+          "required": true,
+          "example": "main",
+          "description": "The server the event happened on, as configured in Admin -> Rust. Also the cooldown subject for broadcasts."
+        },
+        {
+          "name": "server",
+          "type": "string",
+          "required": true,
+          "example": "Runic Gateway | Main",
+          "description": "The server's display name."
+        },
+        {
+          "name": "serverUrl",
+          "type": "url",
+          "required": false,
+          "example": "/rust/servers/main",
+          "description": "Site-relative path to the server's page."
+        },
+        {
+          "name": "title",
+          "type": "string",
+          "required": false,
+          "example": "Main is back online",
+          "description": "A one-line headline naming what happened and where. Core generic bodies use it as the title."
+        },
+        {
+          "name": "intro",
+          "type": "string",
+          "required": false,
+          "example": "Main is back up and taking players.",
+          "description": "One sentence of detail. Core generic bodies use it as the body."
+        },
+        {
+          "name": "subject",
+          "type": "string",
+          "required": true,
+          "example": "main:gc.ended",
+          "description": "The server and the event. The cooldown subject; not meant for display."
+        },
+        {
+          "name": "grid",
+          "type": "string",
+          "required": false,
+          "example": "G7",
+          "description": "The map grid square. Absent when the server has no map geometry yet, or the event is off the map."
+        },
+        {
+          "name": "player",
+          "type": "string",
+          "required": true,
+          "example": "Marisol",
+          "description": "Who killed the last guard, by in-game name."
+        }
+      ]
+    },
+    {
+      "id": "rust.gc.started",
+      "label": "A guarded crate landed",
+      "description": "Guarded Crate dropped a locked crate ringed by guards on a server: on its own schedule, by an admin, or by an event.",
+      "kind": "event",
+      "subjectKey": "subject",
+      "audience": "subscribers",
+      "ceiling": "everyone",
+      "version": 1,
+      "variables": [
+        {
+          "name": "serverId",
+          "type": "string",
+          "required": true,
+          "example": "main",
+          "description": "The server the event happened on, as configured in Admin -> Rust. Also the cooldown subject for broadcasts."
+        },
+        {
+          "name": "server",
+          "type": "string",
+          "required": true,
+          "example": "Runic Gateway | Main",
+          "description": "The server's display name."
+        },
+        {
+          "name": "serverUrl",
+          "type": "url",
+          "required": false,
+          "example": "/rust/servers/main",
+          "description": "Site-relative path to the server's page."
+        },
+        {
+          "name": "title",
+          "type": "string",
+          "required": false,
+          "example": "Main is back online",
+          "description": "A one-line headline naming what happened and where. Core generic bodies use it as the title."
+        },
+        {
+          "name": "intro",
+          "type": "string",
+          "required": false,
+          "example": "Main is back up and taking players.",
+          "description": "One sentence of detail. Core generic bodies use it as the body."
+        },
+        {
+          "name": "subject",
+          "type": "string",
+          "required": true,
+          "example": "main:gc.started",
+          "description": "The server and the event. The cooldown subject; not meant for display."
+        },
+        {
+          "name": "grid",
+          "type": "string",
+          "required": false,
+          "example": "G7",
+          "description": "The map grid square. Absent when the server has no map geometry yet, or the event is off the map."
+        },
+        {
+          "name": "byEvent",
+          "type": "boolean",
+          "required": true,
+          "example": false,
+          "description": "Whether one of this site's events placed it (a Place a guarded crate step)."
+        }
+      ]
+    },
     {
       "id": "rust.kit.entitled",
       "label": "An event rewarded you a kit",