Executor Writes Complexity Tier to Output

Problem

Executor classifies complexity in pty_executor.py but only stores in memory. Not written to -output.jsonl. Downstream consumers must re-classify from prompt file.

Impact

Minor correctness risk from re-classification divergence.

Proposed Solution

Add complexity_tier and turn_budget to output JSONL at pty_executor.py:704. Struggle detector reads tier from output (fallback to prompt classification if missing).

Acceptance Criteria

• Output JSONL contains complexity_tier field
• Backward compatible (new fields only)