fix: harden runtime config lease boundary

backend/src/tht/tht-runner.ts

@@ -141,7 +141,7 @@ export class ThtRunner {
   }
 
   /** Render the pinned registry revision through the shared deterministic lease. */
-  acquireWorkspaceRuntime(workspaceConfigPath: string): RuntimeConfigLease {
+  async acquireWorkspaceRuntime(workspaceConfigPath: string): Promise<RuntimeConfigLease> {
     return this.runtimeConfigLeases().acquireSession(workspaceConfigPath);
   }
 
@@ -283,7 +283,7 @@ export class ThtRunner {
   static readonly DEFAULT_TIMEOUT_MS = 60_000;
   static readonly DWH_TIMEOUT_MS = 120_000;
 
-  run(
+  async run(
     args: string[], workspaceConfigPath?: string, timeoutMs: number = ThtRunner.DEFAULT_TIMEOUT_MS,
   ): Promise<{ code: number; stdout: string; stderr: string }> {
     if (
@@ -293,7 +293,7 @@ export class ThtRunner {
     ) {
       let runtime: RuntimeConfigLease;
       try {
-        runtime = this.acquireWorkspaceRuntime(workspaceConfigPath);
+        runtime = await this.acquireWorkspaceRuntime(workspaceConfigPath);
       } catch (error) {
         return Promise.reject(error);
       }