Task 189: Tech Overview Report Update — Stale Metrics and Content Refresh

Status: DONE

Source

Final review (Task 180) noted several deferred items. Additionally, tech-overview.md has significantly stale metrics:

• "完了タスク 92/93" → actual: 188/188
• "テスト数 1,284" → actual: ~1,985 (TS 1,586 + Rust 350 + E2E 99)
• "コミット数 149" → much higher
• Stale "今後のタスク" and "完了済みの主要タスク" sections
• Missing recently completed features (MDX migration, error range viz, poliastro cross-validation, etc.)

Approach

1. Update all metrics to current values
2. Refresh feature lists (completed tasks, recent tasks)
3. Update architecture description if needed (MDX parser, episode discovery)
4. Add mention of new capabilities since last update
5. Run build + tests to verify