feat(notification): add Android chronometer support

[Et3rnel]

Summary

• add Android chronometer support to notification payload via when, usesChronometer, and chronometerCountDown
• wire new fields across guest JS options, Rust NotificationData/builder API, and Android notification builder/model
• include a .changes entry with matching minor:feat bumps for both Rust and JS notification packages

Motivation

• enable native elapsed/countdown timer notifications for Android use cases like time tracking and ongoing timers

Platform behavior

• Android: maps fields to notification chronometer APIs
• non-Android: fields are ignored and keep current behavior

What it looks like:

Closes #3279