feat(rust): name what a missing RaidableBases helper costs in doctor (PLAN_REDESIGNS §11.4)

RunicGatewayRaids.cs ships beside the bridge from this release (Rust-Plugins
release.yml lists it in the manifest's files), so doctor reports it like the
other helpers: without it the bridge still reports raid bases, but an
event's base cannot be placed, set or locked and despawns on its own timer.

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

src/rustgame/doctor.rs

@@ -347,6 +347,11 @@ fn helper_absence(name: &str) -> String {
              an event zone, because ZoneDomes cannot be called without it"
                 .to_string()
         }
+        "RunicGatewayRaids.cs" => {
+            "the bridge still runs and still reports raid bases, but an event's RaidableBases base \
+             is not the event's: it cannot be placed, set or locked, and despawns on its own timer"
+                .to_string()
+        }
         _ => format!("the bridge still runs without {name}; what it helped with falls back"),
     }
 }