Task 223: Update stale statistics in tech-overview.md and ep04 epoch clarity

Status: DONE

Description

1. tech-overview.md stale stats: Task count (197→222), test counts (2,062→2,306 with updated breakdown), commit count (297→339), DAG nodes (64→65, 317→319 edges), cross-validation count (25→96).
2. ep04.md epoch annotation clarity: Added actual story arrival date (2242-01-07) to the epoch annotation which only showed the 48kt reference scenario end date (2242-04-01).

Files

• reports/data/summary/tech-overview.md
• reports/data/episodes/ep04.md