Workflow/StructuredOutput: retry cap (5) exceeded discards the entire subagent run with no raw-text fallback

A subagent inside a Workflow run hit "StructuredOutput retry cap (5) exceeded — 5 failed calls with no valid output". The subagent had done ~38 minutes / ~314K tokens of real analysis; all of it was discarded because the only return channel was the schema-validated StructuredOutput call.

Expected: when the retry cap is exhausted, fall back to returning the agent's final raw text (flagged as schema-invalid) so the orchestrator can salvage the work, instead of dropping the entire run.

Environment: Claude Code CLI on Windows 11. Observed 2026-06.