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.

build.gradle.kts

@@ -2,6 +2,7 @@
 plugins {
     alias(libs.plugins.android.application) apply false
     alias(libs.plugins.jetbrains.kotlin.android) apply false
+    alias(libs.plugins.compose.compiler) apply false
     id("com.google.gms.google-services") version "4.4.2" apply false
     id("com.google.firebase.crashlytics") version "3.0.2" apply false
     id("com.google.firebase.firebase-perf") version "1.4.2" apply false