Implement File Saving Functionality (Single File + Save All Files as ZIP)

[vikas-saini-7]

Description

Enable users to save files locally from the collaborative editor.
Currently, right-clicking a single file shows a "Save" button, but it doesn't function yet.
Additionally, a new "Save All Files" button should be added in the ChatTabContent component to allow downloading all files in a ZIP format.

Why is this feature useful?

• Allows users to export their work at any time
• Provides a local backup
• Essential for users who collaborate and want to keep a snapshot

How could it work?

For Single File:

• On right-click → "Save" should trigger download of that file’s content

For "Save All Files":

• Add a button at the bottom of the ChatTabContent component
• On click:
  • Collect all files from the current room/project
  • Use a utility library that can handle saving files in zip format
  • Trigger download to the user's device

Screenshots or UI idea

Use shadcn components + tailwind for styling.