feat(rust): Dangerous Treasures — feed, map, Treasure Hunter, Start a Dangerous Treasures event (PLAN_REDESIGNS §14.3.4)

Stage 5 of the §14.3 integration plan, on protocol 14 (docs
rust-link/PROTOCOL.md §20.8).

- dt.started and dt.won are public kinds, dt.ended a staff kind. The new
  dangerousTreasures.js reads each row per viewer: grid and invaderCount for
  everyone, the winner's name for the presence audience (D376), the position,
  the step's key, the winner's Steam id and the invaders for staff.
- Feed lines in the World events filter: "A Dangerous Treasures event has
  started · K12", "Alice won the treasure · K12 · 3 players fought for it".
- Triggers rust.dt.started (with byEvent) and rust.dt.won, public, cooldown
  subject the server, names only.
- eventDangerousTreasures.js: rust.dt.start, "Start a Dangerous Treasures
  event" (risk change, reversible none, budget rust.dt.events), server and
  difficulty. Refused at verify where the server said DT is not loaded or
  console.plugins is false (Rust-Plugins#34). dt-not-ready answers "Dangerous
  Treasures is not ready yet" with retryAfterMs 600000 (D365, D371);
  dt-no-spot retries on core's delay; DT's own refusals are permanent.
- Treasure Hunter (D375): treasuresWon -> treasures_won, the title category
  treasureswon, and a sortable Treasures column shown where the server
  reports DT or a row counts one.
- The map draws a running chest on the world layer; the server settings'
  plugin line names DT and whether a step can start one, from the
  integrations read's new `console`.
- coreApi ^1.15.0, ci/core-ref.json pinned to website main at #215's merge.
  ci/bundle.json ships the two new files; swagger fragment and engagement
  manifest regenerated; README lists DT.

Server 627/627 (16 new in test/dangerousTreasures.test.js) and every check;
client 92/92, build and externals. Booted against the pinned core: 45
triggers, 13 actions, 11 budgets, 21 option sources; 89 routes unchanged.

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

server/engagement/triggers.js

@@ -622,7 +622,54 @@ const WORLD = WORLD_EVENTS.map(([event, label, description, vars]) => ({
   variables: [...SERVER, ...HEADLINE, WORLD_SUBJECT, ...vars],
 }))
 
-const TRIGGERS = Object.freeze([RAID, ...BROADCASTS, ACCOUNT, REWARD, ...CLANS, ...MODERATION, ...NPCS, ...BOSSES, ...WORLD])
+// ── Dangerous Treasures (protocol 14, PLAN_REDESIGNS §14.3.4, §14.3.9) ──────
+//
+// A treasure event opening and being won are triggers, as a world event is
+// (D355): public news, `everyone` the ceiling and `subscribers` the default.
+// The cooldown subject is the server, so a busy hour of treasures is one line
+// per cooldown. `player` is the winner's in-game name only; no Steam id is
+// declared. Its ending is staff's on the feed and raises nothing.
+
+const DT_SUBJECT = { name: 'subject', type: 'string', required: true, example: 'main:dt.won',
+  description: 'The server and the event. The cooldown subject; not meant for display.' }
+const DT_BY_EVENT = { name: 'byEvent', type: 'boolean', required: true, example: false,
+  description: 'Whether one of this site\'s events started it (a Start a Dangerous Treasures event step).' }
+
+const DANGEROUS_TREASURES = [
+  {
+    id: 'rust.dt.started',
+    label: 'A treasure event started',
+    description: 'Dangerous Treasures opened a guarded, burning treasure chest 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, WORLD_GRID, DT_BY_EVENT],
+  },
+  {
+    id: 'rust.dt.won',
+    label: 'A treasure was won',
+    description: 'A player emptied a Dangerous Treasures chest on a server.',
+    kind: 'event',
+    subjectKey: 'subject',
+    audience: 'subscribers',
+    ceiling: 'everyone',
+    version: V1,
+    variables: [
+      ...SERVER,
+      ...HEADLINE,
+      DT_SUBJECT,
+      WORLD_GRID,
+      { name: 'player', type: 'string', required: false, example: 'Marisol',
+        description: 'Who emptied the chest, by in-game name.' },
+      { name: 'invaders', type: 'int', required: true, example: 3,
+        description: 'How many players fought for it, the winner included.' },
+    ],
+  },
+]
+
+const TRIGGERS = Object.freeze([RAID, ...BROADCASTS, ACCOUNT, REWARD, ...CLANS, ...MODERATION, ...NPCS, ...BOSSES, ...WORLD, ...DANGEROUS_TREASURES])
 
 const TRIGGER_IDS = Object.freeze(Object.fromEntries(TRIGGERS.map((t) => [t.id, t.id])))