Add status page identity visibility settings

[jbrooksuk]

Summary

• add independent public status-page toggles for the site name and About content
• retain the site name and About content in document metadata
• default new installs to hide the site name while leaving About visible
• localize the new settings in every shipped locale

Validation

• php -l for changed PHP files
• git diff --check
• Pest not run: this worktree has no Composer vendor/ directory