report_issue tool architecture: eliminate lossy extraction step

- Add report_issue as inline tool (model reports bugs during investigation)
- Remove _extract_issues second LLM call, _strict_schema, Pydantic models
- Remove _call_opus (dead after always-tool path)
- Raise max_tool_rounds from 25 to 50
- WarpGrep listed first as primary investigation tool
- Rewrite system prompt: one-liner categories with e.g., evolved elements
  (behavioral regression check, language pitfalls, anti-hallucination rule)