Bump versionCode to 7 / versionName to 1.7.0 for proper update installs

Android requires versionCode to increase for update-over-top installs.
Without this, reinstalling would say "App not installed" on some devices.

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

app/build.gradle.kts

@@ -11,8 +11,8 @@ android {
         applicationId = "com.pixel10.ai"
         minSdk = 31
         targetSdk = 35
-        versionCode = 1
-        versionName = "1.0.0"
+        versionCode = 7
+        versionName = "1.7.0"
     }
 
     buildTypes {