Increase max delay limit to 48 hours for scenes and reactions

[DrzwiPercepcji]

What does this PR change?

• Raise the maximum delay for scene operations from 1 hour to 48 hours (backend validation, UI slider, translations).
• Apply the same 48-hour limit to reaction condition duration (duration_sec).
• Add unit tests for the new boundaries.

Checklist

• Linked issue / rationale provided: Increase maximum time limit for scenes delay #1065
• Code follows existing style and conventions
• Documentation updated if needed
• CLA accepted (requested automatically after opening the PR)
• Tests added/updated (if applicable)
• No secrets in logs/config