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

client/src/components/Leaderboard.jsx

@@ -46,6 +46,10 @@ const COLUMNS = [
 // 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) }
 
+// Warden (PLAN_REDESIGNS §14.3.5, D375): guarded crates cleared, shown on the
+// same rule from the server's `guardedCrate`.
+const GUARDED = { key: 'guardedWon', label: 'Crates cleared', sort: 'guardedWon', value: (r) => count(r.guardedWon) }
+
 const BALANCE = { key: 'balance', label: 'Coins', sort: 'balance', value: (r) => coins(r.balance) }
 
 export default function Leaderboard({ serverId, wipeId, sort, onSort }) {
@@ -104,6 +108,7 @@ function Overall({ serverId, wipeId, sort, onSort }) {
   const columns = [
     ...COLUMNS,
     ...(data && data.dangerousTreasures ? [TREASURES] : []),
+    ...(data && data.guardedCrate ? [GUARDED] : []),
     ...(data && data.economics ? [BALANCE] : []),
   ]
   // Present on every row or on none — the server decides per request.