Task 470: Add Visualization Charts to Ship Kestrel Summary Report

Status: DONE

Summary

The ship-kestrel.md summary report has only 3 charts despite being the most data-rich summary report. Add 2 high-impact charts:

1. Acceleration comparison chart (48,000t vs 300t): The central "mass mystery" — episode-by-episode grouped comparison showing the ~160x gap at 48,000t vs achievable acceleration at 300t. This is the most important visualization in the entire report.
2. Mass hypothesis evaluation chart: The 4-hypothesis comparison (慣性補償/SF慣例/推進剤消費/DWT解釈) across evaluation dimensions, currently a text-only table.

Plan

1. Write content validation tests (TDD red)
2. Add 2 bar charts to ship-kestrel.md
3. Verify tests pass (TDD green)
4. Commit

Impact

• Brings ship-kestrel.md from 3 to 5 visualizations
• Visualizes the central 160x mass mystery thesis
• Makes hypothesis evaluation immediately scannable