fix: close Workbench SSE inspection cleanly

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tools/src/workbench-cli.ts

@@ -60,7 +60,7 @@ async function inspectEvents(parsed: Parsed, env: Record<string, string | undefi
     if (!response.ok || !response.body) throw codedError("workbench_sse_open_failed", `Workbench SSE returned HTTP ${response.status}`);
     const reader = response.body.getReader();
     const decoder = new TextDecoder();
-    while (true) {
+    readStream: while (true) {
       const item = await reader.read();
       if (item.done) break;
       buffer += decoder.decode(item.value, { stream: true });
@@ -70,7 +70,10 @@ async function inspectEvents(parsed: Parsed, env: Record<string, string | undefi
         buffer = buffer.slice(boundary + 2);
         const frame = parseSseBlock(block);
         if (frame) frames.push(frame);
-        if (frames.filter((entry) => entry.name === "hwlab.event.v1").length >= minEvents) controller.abort();
+        if (frames.filter((entry) => entry.name === "hwlab.event.v1").length >= minEvents) {
+          await reader.cancel();
+          break readStream;
+        }
         boundary = buffer.indexOf("\n\n");
       }
     }