fix(e2b): harden remote teardown transactions

packages/e2b/subprocess-e2b/src/output.ts

@@ -66,6 +66,7 @@ export class E2BOutputReader implements SubprocessOutputReader {
   private chunks: Buffer[] = []
   private retainedBytes = 0
   private totalBytes = 0
+  private spillValid = true
 
   /**
    * Create a bounded reader over one remote spill path.
@@ -84,6 +85,11 @@ export class E2BOutputReader implements SubprocessOutputReader {
     return this.totalBytes
   }
 
+  /** Stop advertising a remote spill whose writer did not reach clean EOF. */
+  invalidateSpill(): void {
+    this.spillValid = false
+  }
+
   /**
    * Append one byte-faithful decoded transport event.
    * @param bytes - Raw command bytes recovered from the ASCII SDK transport.
@@ -120,7 +126,7 @@ export class E2BOutputReader implements SubprocessOutputReader {
       text: retained.subarray(start).toString('utf8'),
       nextOffset: this.totalBytes,
       lossy,
-      ...(lossy && this.maxSpillBytes !== undefined && this.totalBytes <= this.maxSpillBytes
+      ...(lossy && this.spillValid && this.maxSpillBytes !== undefined && this.totalBytes <= this.maxSpillBytes
         ? { spillPath: this.spillPath }
         : {}),
     }