Add ui-tiles-expressive module documentation to README

[Copilot]

The ui-tiles-expressive module was missing from the README documentation despite being published to Maven Central.

Changes

• Preview table: Added "Ui tiles expressive" section with SettingsButtonGroup component
• Install section: Added module configuration for Groovy, Kotlin DSL, and Gradle version catalogs
• Usage section: Added component documentation with code example and Material 3 Expressive API requirement note

Example

// Gradle (Kotlin DSL)
implementation("com.github.alorma.compose-settings:ui-tiles-expressive:$version")

// Catalog
composeSettings-ui-expressive = { 
  group = "com.github.alorma.compose-settings", 
  name = "ui-tiles-expressive", 
  version.ref = "compose-settings" 
}

The module provides SettingsButtonGroup, which uses Material 3 Expressive's OutlinedToggleButton for multi-option selection within settings screens.

Original prompt

On the readme, add the configuration for the expressive module, as it's missing, alongside the others

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.