Add UI Layer snippets

[djubinville]

Extracted code snippets for page:

https://developer.android.com/topic/architecture/ui-layer

in file: compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt

List of modifications:

UI layer page: Migrated 8 Kotlin code snippets to

android_architecture_ui_layer_news_ui_state
android_architecture_ui_layer_viewmodel_expose_state
android_architecture_ui_layer_viewmodel_mutable_state
android_architecture_ui_layer_viewmodel_fetch_articles
android_architecture_ui_layer_news_can_bookmark
android_architecture_ui_layer_news_fetching_state
android_architecture_ui_layer_latest_news_screen
android_architecture_ui_layer_news_user_messages

UI layer page: In android_architecture_ui_layer_viewmodel_expose_state, applied the D23 twin pattern on val uiState: NewsUiState = /* ... */ with silent exclude for compiling NewsUiState() to ensure clean compilation while preserving the placeholder on DAC per review feedback.

Snippets not migrated:

None; all 8 snippets on the page were migrated.

cc: @kkuan2011

[snippet-bot]

Here is the summary of changes.

You are about to add 8 region tags.

• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:37, tag android_architecture_ui_layer_news_ui_state
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:61, tag android_architecture_ui_layer_viewmodel_expose_state
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:81, tag android_architecture_ui_layer_viewmodel_mutable_state
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:109, tag android_architecture_ui_layer_viewmodel_fetch_articles
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:142, tag android_architecture_ui_layer_news_can_bookmark
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:154, tag android_architecture_ui_layer_news_fetching_state
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:170, tag android_architecture_ui_layer_latest_news_screen
• compose/snippets/src/main/java/com/example/compose/snippets/architecture/UiLayer.kt:189, tag android_architecture_ui_layer_news_user_messages

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[kkuan2011]

Looks great! Thank you David!