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

server/engagement/triggers.js

@@ -669,7 +669,50 @@ const DANGEROUS_TREASURES = [
   },
 ]
 
-const TRIGGERS = Object.freeze([RAID, ...BROADCASTS, ACCOUNT, REWARD, ...CLANS, ...MODERATION, ...NPCS, ...BOSSES, ...WORLD, ...DANGEROUS_TREASURES])
+// ── Guarded Crate (protocol 14, PLAN_REDESIGNS §14.3.5, §14.3.9) ────────────
+//
+// A guarded crate landing and being cleared are triggers, as Dangerous
+// Treasures' are: public news, the server the cooldown subject. `player` is the
+// clearer's in-game name only. A crate whose guards went with nobody killing
+// the last (NpcSpawn reloaded under it) and one that timed out raise nothing:
+// neither is news.
+
+const GC_BY_EVENT = { name: 'byEvent', type: 'boolean', required: true, example: false,
+  description: 'Whether one of this site\'s events placed it (a Place a guarded crate step).' }
+
+const GUARDED_CRATE = [
+  {
+    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: V1,
+    variables: [...SERVER, ...HEADLINE, { ...DT_SUBJECT, example: 'main:gc.started' }, WORLD_GRID, GC_BY_EVENT],
+  },
+  {
+    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: V1,
+    variables: [
+      ...SERVER,
+      ...HEADLINE,
+      { ...DT_SUBJECT, example: 'main:gc.ended' },
+      WORLD_GRID,
+      { name: 'player', type: 'string', required: true, example: 'Marisol',
+        description: 'Who killed the last guard, by in-game name.' },
+    ],
+  },
+]
+
+const TRIGGERS = Object.freeze([RAID, ...BROADCASTS, ACCOUNT, REWARD, ...CLANS, ...MODERATION, ...NPCS, ...BOSSES, ...WORLD, ...DANGEROUS_TREASURES, ...GUARDED_CRATE])
 
 const TRIGGER_IDS = Object.freeze(Object.fromEntries(TRIGGERS.map((t) => [t.id, t.id])))