Refactor: Update dependencies and Gradle configuration

This commit updates various dependencies and reconfigures Gradle settings to newer versions and standards.

Specific changes include:

-   Updated Android Gradle Plugin to 8.6.1
-   Updated Kotlin to 2.1.20
-   Updated Compose Compiler to 1.5.15
-   Updated Compose BOM to 2025.04.01
-   Updated Hilt to 2.54
-   Updated KSP to 2.1.20-2.0.0
-   Updated other dependencies like Navigation, Core-Ktx, Lifecycle, Activity Compose, Room, Paging, Coil, Serialization Json
-   Migrated to Java 21
-   Applied Compose plugin
- Updated target and compile SDK to 35
- updated jvm target to Java 21

build.gradle.kts

@@ -4,4 +4,5 @@ plugins {
     alias(libs.plugins.kotlin.android) apply false
     alias(libs.plugins.hilt) apply false
     alias(libs.plugins.ksp) apply false
+    alias(libs.plugins.compose.compiler) apply false
 }