ADT fallback: Accept headers for FUNC; G0189 accepted; regen2 results

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014aUaQeLnwbb1zTpN7kHeat

harness/proxy.py

@@ -153,7 +153,8 @@ class ToolProxy:
                 self.adt = AdtClient()
             done, msgs = self.adt.write_activate(uri, name.upper(), args.get("source", ""))
         except Exception as e:  # noqa: BLE001  keep the EPOD result when the fallback fails
-            self.fallbacks.append({"object": name, "error": str(e)[:200]})
+            body = e.read().decode(errors="replace")[:600] if hasattr(e, "read") else ""
+            self.fallbacks.append({"object": name, "error": str(e)[:200], "body": body})
             return err, text
         self.fallbacks.append({"object": name, "activated": done})
         out = {"success": done,