fix(FN-4813): avoid isolation transition double-write in project route

Fusion-Task-Id: FN-4813
Fusion-Task-Lineage: 846893a5-2afa-4817-8f64-8c444d2fd713

packages/core/src/central-core.ts

@@ -519,6 +519,7 @@ export class CentralCore extends EventEmitter<CentralCoreEvents> {
     nextMode: IsolationMode,
     opts: { force?: boolean } = {}
   ): Promise<{ ok: true } | { ok: false; reason: string; activeTaskCount?: number }> {
+    // Runtime restart force semantics are handled by HybridExecutor/ProjectManager.
     void opts;
     this.ensureInitialized();
 

packages/dashboard/src/routes/register-project-routes.ts

@@ -615,6 +615,7 @@ export const registerProjectRoutes: ApiRouteRegistrar = (ctx) => {
                 activeTaskCount: transition.activeTaskCount ?? 0,
               });
             }
+            delete updates.isolationMode;
           } else {
             transitionDeferred = true;
           }