fix: add EPUB narration lock-screen controls

[van-geaux]

Summary

• Add lock-screen and Android media controls for EPUB 3 read-along narration and EPUB TTS.
• Keep one custom multiline narration notification, with Lagrange branding and custom transport actions, instead of a duplicate/default player.
• Synchronize custom play/pause actions with actual and requested playback state.
• Start TTS from the selected word or phrase by matching normalized selected text in utterances.
• Leave audiobook notification behavior unchanged.

Verification

• Focused TTS tests passed.
• Full JVM unit-test suite passed.
• Main and Android-test Kotlin compilation passed.
• Lint passed.
• Debug and Android-test APK assembly passed.
• Connected-device validation was performed by the maintainer on 100.90.237.107:34387, including custom notification behavior, play/pause state, logo, lock-screen controls, and TTS selected-text playback.
• Handoff APK: app/build/outputs/apk/debug/Lagrange-debug-202610091546.apk
• SHA-256: 4ba96c7a633ae97adf70408fab40f8721144d809f5683145f2ffdc51d90b3713

Closes #240