[FEATURE] Notes Module: Export/Save notes as Markdown, PDF, Plain Text, or Word documents

[arindam-sahoo]

Is your feature request related to a problem? Please describe.
Currently, there is no direct way to export notes out of KoBar. All note content is stored within the application's internal database. If I want to share a note, open it in another text editor (like VS Code or Word), print it, or keep a backup file, I have to manually copy all text and paste it into a file outside KoBar. This is tedious and often results in losing rich-text formatting (like bolding, lists, and images).

Describe the solution you'd like
I would like to see an Export or Save As option added to the Notes module. When viewing/editing a note, a button should allow the user to save the current note to their computer in one of the following formats:

• Markdown (.md): Exports the rich-text structure to clean Markdown format.
• Plain Text (.txt): Exports the note's content as unformatted plain text.
• PDF (.pdf): Renders the note as a print-ready PDF file.
• Word Document (.docx): Exports the note in a format compatible with Microsoft Word.

This would be an enhancement to the existing Notes tool, potentially integrated into the Note Editor toolbar or next to the Note Title.

Describe alternatives you've considered

• Copy as Markdown/HTML: Adding a button to copy the note content formatted as Markdown or HTML to the clipboard. While helpful, this still requires opening another app, creating a new file, pasting it, and saving it manually.
• Bulk JSON Backup: A setting to backup all notes as a single JSON file. This is great for app backups but doesn't help with exporting a single note for general use or sharing.

Additional context or Mockups
A simple export icon button (such as the Material Icon download or ios_share) could be added to the formatting toolbar:

• Clicking the button opens a small dropdown menu:
  • 📥 Export as Markdown (.md)
  • 📄 Export as Plain Text (.txt)
  • 📕 Export as PDF (.pdf)
  • 📝 Export as Word (.docx)
• Selecting an option triggers the native OS save dialog to choose the file location.