Implement sync prompt field width with chats width

[itsmartashub]

Sync Feature for Textarea Prompt:

• Implement a sync option for the textarea prompt width, represented by a switch or checkbox.
• When enabled, the textarea prompt width dynamically follows the chat width, ensuring a consistent layout.
• If disabled, users can set a custom width for the textarea prompt independently.
• Cross page consistency (storage saving)

Locked Icon Indication:

• Add a locked SVG icon into custom prompt width option to visually indicate the state of the prompt field.
• When syncing is enabled, display the locked icon and styling to signify that the prompt field is locked to the chat width.
• The icon should be visually distinct but subtle, providing a clear indication of the sync state without being intrusive.