feat(build): add play build flavor for paywall

app/build.gradle.kts

@@ -58,6 +58,19 @@ android {
             )
         }
     }
+
+    flavorDimensions += "version"
+    productFlavors {
+        create("foss") {
+            dimension = "version"
+            isDefault = true
+        }
+        create("play") {
+            dimension = "version"
+            versionNameSuffix = "-play"
+        }
+    }
+
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_17
         targetCompatibility = JavaVersion.VERSION_17
@@ -103,6 +116,8 @@ dependencies {
     implementation(libs.androidx.room.ktx)
     ksp(libs.androidx.room.compiler)
 
+    "playImplementation"(libs.purchases)
+
     testImplementation(libs.junit)
 
     androidTestImplementation(libs.androidx.junit)

app/src/play/AndroidManifest.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (c) 2025 Nishant Mishra
+  ~
+  ~ This file is part of Tomato - a minimalist pomodoro timer for Android.
+  ~
+  ~ Tomato is free software: you can redistribute it and/or modify it under the terms of the GNU
+  ~ General Public License as published by the Free Software Foundation, either version 3 of the
+  ~ License, or (at your option) any later version.
+  ~
+  ~ Tomato is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+  ~ the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+  ~ Public License for more details.
+  ~
+  ~ You should have received a copy of the GNU General Public License along with Tomato.
+  ~ If not, see <https://www.gnu.org/licenses/>.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <uses-permission android:name="com.android.vending.BILLING" />
+</manifest>