feat: initialize GaCy Android project foundation (Kotlin, Jetpack Compose, Material 3)

app/src/main/java/com/gacy/android/MainActivity.kt

@@ -0,0 +1,44 @@
+package com.gacy.android
+
+import android.Manifest
+import android.content.pm.PackageManager
+import android.os.Build
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
+import com.gacy.android.ui.screens.MainScreen
+import com.gacy.android.ui.theme.GaCyTheme
+
+class MainActivity : ComponentActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        requestAppPermissions()
+
+        setContent {
+            GaCyTheme {
+                MainScreen()
+            }
+        }
+    }
+
+    private fun requestAppPermissions() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            if (ContextCompat.checkSelfPermission(
+                    this,
+                    Manifest.permission.POST_NOTIFICATIONS
+                ) != PackageManager.PERMISSION_GRANTED
+            ) {
+                ActivityCompat.requestPermissions(
+                    this,
+                    arrayOf(Manifest.permission.POST_NOTIFICATIONS),
+                    101
+                )
+            }
+        }
+    }
+}