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/MapView.jsx

@@ -47,6 +47,7 @@ const COLOURS = {
   supply: '#66bb6a',
   crate: '#ffee58',
   treasure: '#ffab00',
+  guarded: '#ff7043',
   event: '#ce93d8',
   boss: '#d500f9',
   online: '#ffffff',
@@ -67,6 +68,8 @@ const WORLD_NAMES = {
   crate: 'Locked crate',
   // Dangerous Treasures (§14.3.4): its running chests.
   treasure: 'Dangerous Treasures chest',
+  // Guarded Crate (§14.3.5): a crate whose guards still stand.
+  guarded: 'Guarded crate',
   boss: 'Boss',
 }