feat: Implement 'Local Mode' toggles for enhanced privacy and offline use

[imtuyethan]

• [X] I have searched the existing issues

Background

https://discord.com/channels/1107178041848909847/1280103773867606016 Users are increasingly concerned about privacy and data security when using AI assistants. Some may want to ensure their interactions remain entirely local and offline for sensitive work or personal preference. Currently, Jan doesn't have a simple way to guarantee fully offline, private operation.

Feature request

Implement a "Local Mode" toggle in Jan with two levels of privacy:

• "Local AI" button: Disables use of online models/API models, turns off "preserve model settings", and disables all extensions used for API connections.
• "Fully Offline" button: Completely disables Jan's internet connection, ensuring absolute privacy.

Proposed Implementation

1. Add a new "Privacy Mode" section in Jan's settings.
2. Implement the "Local AI" toggle:
   • When enabled, force use of only local models
   • Disable "preserve model settings" option
   • Temporarily disable all API-related extensions
3. Implement the "Fully Offline" toggle:
   • When enabled, completely cut off Jan's internet access at the application level
   • This should override and include all "Local AI" settings
4. Add clear UI indicators when either mode is active
5. Implement graceful handling of features that require internet when in these modes (e.g. greying out options, informative tooltips)

Additional Notes

• Market this as an "extra secure option" for privacy-conscious users
• Consider adding a short explanation of what each mode does in the UI
• Ensure thorough testing to guarantee no data leakage when these modes are active
• This feature aligns with Jan's commitment to user privacy and data ownership

[0xSage]

Hm do any other apps do this? It's more that they show you are in offline mode. e.g. a broken cloud, when you are in offline mode.

I think introduce an "offline feature" to toggle off features will introduce complicated app / ui logic and lead to many user tickets. I think the best demonstration is just the fact that Jan can run without wifi... which it currently does.