Add ML Kit translation support for post cards and post detail views

[nove-b]

Summary

This PR adds ML Kit-based translation support for posts across the app.

Users can now translate post content from both timeline post cards and post detail screens, and toggle back to the original text after translation.

Changes

• add ML Kit Translate and Language ID dependencies
• add coroutine Play Services integration for await()
• add translation-related string resources
• add translate action to the post card engagement bar
• add translate action to the post detail action row
• detect the user's selected app/device language as the translation target
• show translation loading and error states
• cache translated text in UI state for quick toggling between translated and original content

Implementation Notes

• post HTML is converted to plain text before translation
• the source language is detected with ML Kit Language Identification
• translation models are downloaded on demand via ML Kit
• if the detected source language matches the target language, the original text is shown

Tested

• built the app successfully with ./gradlew assembleDebug
• verified the translation UI is available on both post cards and post detail screens

Notes

• translated content is currently displayed as plain text, not re-rendered as HTML
• links and mentions in translated output are not preserved as interactive elements

[malkoG]

Thansk for your contribution!