Improved timezone selection and expired channel handling

Added:

• New utility function converts strings to numbers for better data processing.
• Options now let you handle expired channels in the compose modal.
• Configuration added to allow expired channels in posts.
  Improved:
• Country and timezone selection works smoother with better value handling.
• Approval button shows clearer messages and tooltips about permissions.
• Brand dropdown safely loads icons to avoid issues.
• Emoji picker repositioned for easier post editing.
• Rescheduling posts uses the correct HTTP method.
• Channel hover interactions are smoother around expired channels.
• Validation messages wrap text better for readability.
• Mobile sidebar shows organization names safely without errors.