Fix manage page layout and clarify home and recent event copy

[felixgollnhuber]

Summary

• fix the manage page layout so the heatmap uses a single content column when the embedded sidebar is disabled
• tighten manage page spacing and extend bottom padding and background gradient to avoid the background ending too early
• update the home hero slogan in English and German for clearer positioning
• rename recent event actions to clearer labels for board access vs organizer management
• refresh the public logo asset
• add regression coverage for the manage heatmap layout and recent event action labels

Testing

• pnpm verify
• pnpm test:run src/components/recent-events-section.test.tsx