Add version management with auto-bump script

Version is tracked in version.properties and read by build.gradle.kts.
Run ./bump-version.sh [major|minor|patch] before release builds.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/build.gradle.kts

@@ -14,6 +14,15 @@ val keystoreProperties = Properties().apply {
     }
 }
 
+// Load version from version.properties
+val versionProperties = Properties().apply {
+    load(rootProject.file("version.properties").inputStream())
+}
+val vMajor = versionProperties["versionMajor"].toString().toInt()
+val vMinor = versionProperties["versionMinor"].toString().toInt()
+val vPatch = versionProperties["versionPatch"].toString().toInt()
+val vCode = versionProperties["versionCode"].toString().toInt()
+
 android {
     namespace = "no.naiv.tiltshift"
     compileSdk = 35
@@ -34,8 +43,8 @@ android {
         applicationId = "no.naiv.tiltshift"
         minSdk = 35
         targetSdk = 35
-        versionCode = 1
-        versionName = "1.0.0"
+        versionCode = vCode
+        versionName = "$vMajor.$vMinor.$vPatch"
 
         vectorDrawables {
             useSupportLibrary = true