Refactor: Upgrade Coil to v3 and update dependencies

- Upgraded image loading library from Coil 2 to Coil 3, updating related APIs across the app.
- Migrated `viewModel()` to a singleton pattern for `AgentViewModel` to optimize instantiation.
- Updated various dependencies, including Android Gradle Plugin, Kotlin, Compose, and other libraries.
- Upgraded Gradle wrapper to version 8.11.1.
- Removed deprecated `windowInsets` and `animateItemPlacement` parameters in Compose components to align with latest API versions.

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 #Fri Jun 14 03:23:01 CST 2024
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists