Refresh Board-Man GitHub presence and screenshots

[uniplanck]

Summary

• rebuild the English and Japanese READMEs around the current Board-Man product
• update the remaining localized READMEs with current release status and Templates terminology
• generate English, compact-width, Settings, and Japanese screenshots from isolated demo clipboard profiles
• add contribution, support, security, conduct, issue, pull-request, changelog, CODEOWNERS, and Dependabot guidance
• expand CI with repository validation and a macOS build-and-test job
• keep screenshot export Debug-only and restore the canonical app and a harmless clipboard value after capture

GitHub repository updates

• refreshed description and repository topics
• added dependencies, UI, privacy, macOS, and needs-reproduction labels
• clarified that Funding links support the upstream Clipy project

Verification

• Debug build succeeded
• 71 tests in 10 suites passed
• screenshot workflow produced 800x560, 700x560, 800x820, and 800x560 PNGs
• shell syntax, YAML parsing, Markdown local links, whitespace, and bounded secret-pattern scans passed
• canonical /Applications app was restored after isolated screenshot capture

Privacy

The screenshots contain deterministic demo clipboard text only. Temporary profiles are deleted after each run, and the screenshot hook is compiled only in Debug builds.