Improve high-DPI layouts and documentation

[papanda925]

Summary

• rewrite the README with Japanese-first setup, sample outputs, DPI concepts, limitations, and troubleshooting
• replace fixed coordinates that placed buttons outside the original forms
• use TableLayoutPanel and FlowLayoutPanel for DPI- and font-tolerant layouts
• use the current Windows dialog font instead of an unnamed 45-pixel font
• preserve standard OK/Cancel, Enter/Esc, and pipeline output behavior
• dispose forms and cloned fonts deterministically
• add PowerShell parser checks and repository-level high-DPI conventions in GitHub Actions

Validation

• local structural and whitespace checks passed
• Windows GitHub Actions parses all four scripts without showing the dialogs
• visual checks at 100%, 125%, 150%, and 200% scaling remain required, so this PR is Draft

Compatibility

The samples remain standalone Windows PowerShell scripts with no third-party modules.