debug: dump raw NDJSON for issue #439 investigation

Saves Claude Code stdout to /tmp/uwf-ndjson-dump/ before parsing.
Temporary — remove after root cause confirmed.

Refs #439

packages/workflow-agent-claude-code/src/claude-code.ts

@@ -1,4 +1,5 @@
 import { spawn } from "node:child_process";
+import { mkdirSync, writeFileSync } from "node:fs";
 import type { Store } from "@uncaged/json-cas";
 import {
   type AgentContext,
@@ -117,7 +118,17 @@ function spawnClaudeResume(
   ]);
 }
 
+const NDJSON_DUMP_DIR = "/tmp/uwf-ndjson-dump";
+
 async function processClaudeOutput(stdout: string, store: Store): Promise<AgentRunResult> {
+  // Debug dump: save raw NDJSON for issue #439 investigation
+  try {
+    mkdirSync(NDJSON_DUMP_DIR, { recursive: true });
+    writeFileSync(`${NDJSON_DUMP_DIR}/${Date.now()}.ndjson`, stdout);
+  } catch {
+    // ignore dump failures
+  }
+
   const parsed = parseClaudeCodeStreamOutput(stdout);
 
   if (parsed !== null) {