Add google signin & navigation.

app/src/main/java/com/pixelized/rplexicon/MainActivity.kt

@@ -0,0 +1,48 @@
+package com.pixelized.rplexicon
+
+import android.app.Activity
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.staticCompositionLocalOf
+import androidx.compose.ui.Modifier
+import com.pixelized.rplexicon.ui.navigation.ScreenNavHost
+import com.pixelized.rplexicon.ui.theme.LexiconTheme
+import dagger.hilt.android.AndroidEntryPoint
+
+val LocalActivity = staticCompositionLocalOf<Activity> { error("Activity not available") }
+
+@AndroidEntryPoint
+class MainActivity : ComponentActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        setContent {
+            LexiconTheme {
+                CompositionLocalProvider(
+                    LocalActivity provides this
+                ) {
+                    Scaffold(
+                        content = { padding ->
+                            Surface(
+                                modifier = Modifier
+                                    .fillMaxSize()
+                                    .padding(paddingValues = padding),
+                                color = MaterialTheme.colorScheme.background
+                            ) {
+                                ScreenNavHost()
+                            }
+                        }
+                    )
+                }
+            }
+        }
+    }
+}