feat: Implement initial authentication, multi-environment support, and core app infrastructure.

android/app/build.gradle.kts

@@ -20,20 +20,35 @@ android {
     }
 
     defaultConfig {
-        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId = "com.requestn.real_estate_mobile"
-        // You can update the following values to match your application needs.
-        // For more information, see: https://flutter.dev/to/review-gradle-config.
         minSdk = flutter.minSdkVersion
         targetSdk = flutter.targetSdkVersion
         versionCode = flutter.versionCode
         versionName = flutter.versionName
     }
 
+    flavorDimensions += "flavor-type"
+
+    productFlavors {
+        create("local") {
+            dimension = "flavor-type"
+            applicationIdSuffix = ".local"
+            resValue("string", "app_name", "RE-QuestN Local")
+        }
+        create("demo") {
+            dimension = "flavor-type"
+            applicationIdSuffix = ".demo"
+            resValue("string", "app_name", "RE-QuestN Demo")
+        }
+        create("dev") {
+            dimension = "flavor-type"
+            applicationIdSuffix = ".dev"
+            resValue("string", "app_name", "RE-QuestN Dev")
+        }
+    }
+
     buildTypes {
         release {
-            // TODO: Add your own signing config for the release build.
-            // Signing with the debug keys for now, so `flutter run --release` works.
             signingConfig = signingConfigs.getByName("debug")
         }
     }

android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <application
-        android:label="real_estate_mobile"
+        android:label="@string/app_name"
         android:name="${applicationName}"
         android:icon="@mipmap/ic_launcher">
         <activity