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

client/src/components/Leaderboard.jsx

@@ -41,6 +41,11 @@ const COLUMNS = [
 // so with `economics` on the answer — so the column is there exactly when the
 // rows carry it. Sorting by it ranks only balances above the starting balance
 // (D336), which is why a fresh wipe's sort shows nobody.
+// Treasure Hunter (PLAN_REDESIGNS §14.3.4, D375): Dangerous Treasures won. The
+// server says `dangerousTreasures` where the server reports the plugin, or the
+// rows already count a treasure, so the column is there exactly then.
+const TREASURES = { key: 'treasuresWon', label: 'Treasures', sort: 'treasuresWon', value: (r) => count(r.treasuresWon) }
+
 const BALANCE = { key: 'balance', label: 'Coins', sort: 'balance', value: (r) => coins(r.balance) }
 
 export default function Leaderboard({ serverId, wipeId, sort, onSort }) {
@@ -96,7 +101,11 @@ function Overall({ serverId, wipeId, sort, onSort }) {
   )
 
   const rows = data ? data.leaderboard : []
-  const columns = data && data.economics ? [...COLUMNS, BALANCE] : COLUMNS
+  const columns = [
+    ...COLUMNS,
+    ...(data && data.dangerousTreasures ? [TREASURES] : []),
+    ...(data && data.economics ? [BALANCE] : []),
+  ]
   // Present on every row or on none — the server decides per request.
   const showLastSeen = rows.some((row) => 'lastSeen' in row)