Add pro-active conversation trigger baded on external events

Enable main agent to sense incoming emails and proactively start the conversation whether in form of app notification, speech (after implmenting in device tts convertion), and text based when the app is opened (being used by user.)

* Case I: App notification -> When (APP is closed).
* Case II: Speech notification -> When (APP is closed).
* Case III: Text msg from ai -> When (APP is opened, being used by user).

The issue names no files, tests, or entry points. First map how incoming emails are detected and how the app handles closed versus open states, then clarify the notification, speech, and text requirements before implementation; done means each listed case triggers the intended response.

Written by the indexing model from the issue text.