Add chatbot implementation via Gemini

[lethargicpanda]

Add chatbot implementation using the Gemini API

• Chatbot functionality
• Button in settings to toggle the feature

Chatbot in action	Toggle button in settings

[donovanfm]

I discussed this with @lethargicpanda and we decided that he would update this to work without an API key. Currently, the project won't build if you don't provide a Gemini API Key. In the update, if a developer doesn't provide an API key, then the smart chatbot feature will be disabled on the Settings page with a note explaining why. This change is meant to reduce developer friction, especially if someone wants to use SociaLite without the Gemini functionality.

[lethargicpanda]

I discussed this with @lethargicpanda and we decided that he would update this to work without an API key. Currently, the project won't build if you don't provide a Gemini API Key. In the update, if a developer doesn't provide an API key, then the smart chatbot feature will be disabled on the Settings page with a note explaining why. This change is meant to reduce developer friction, especially if someone wants to use SociaLite without the Gemini functionality.

Updated!

[Jaehwa-Noh]

I think it would be better to use secrets for security issues as you do before, and add this secrets.defaults.properties file rather than remove secrets. https://github.com/android/nowinandroid/blob/main/secrets.defaults.properties

[donovanfm]

This looks good to me to merge. There are a few follow ups that would make this feature more polished. @madebymozart for viz.

1) Move the API key out of a standard string. (I think this one is already on your radar.) 2) Improve feedback to the user when GenAI fails, including if there's no network connection on the phone. 3) Add some documentation on this feature to the README since it's a flagship Google feature.