Publish a signed Play AAB from Deploy Prod.

Closes #121. Supersedes the separate Deploy Android workflow in #58 by attaching hesychia-<version>-<code>.aab to an android-v* Gitea release after the prod web deploy.

llm-fe/android/app/build.gradle

@@ -1,5 +1,17 @@
 apply plugin: 'com.android.application'
 
+// Last bundle recorded in git. Prod deploy passes -PhesychiaVersionCode and
+// -PhesychiaVersionName; these stay the floor when those properties are absent.
+def hesychiaVersionCodeFloor = 1
+def hesychiaVersionNameFloor = "0.1.0"
+
+// Resolve before the android block. A parenthesized expression on the versionCode
+// setter is parsed as a cast of the setter result, so AGP throws "Value is null".
+def hesychiaVersionCodeProp = project.findProperty('hesychiaVersionCode')?.toString()?.trim()
+def hesychiaVersionNameProp = project.findProperty('hesychiaVersionName')?.toString()?.trim()
+def resolvedVersionCode = hesychiaVersionCodeProp ? hesychiaVersionCodeProp.toInteger() : hesychiaVersionCodeFloor
+def resolvedVersionName = hesychiaVersionNameProp ? hesychiaVersionNameProp : hesychiaVersionNameFloor
+
 def keystorePropertiesFile = rootProject.file('keystore.properties')
 def keystoreProperties = new Properties()
 if (keystorePropertiesFile.exists()) {
@@ -13,8 +25,8 @@ android {
         applicationId "ai.hesychia.chat"
         minSdkVersion rootProject.ext.minSdkVersion
         targetSdkVersion rootProject.ext.targetSdkVersion
-        versionCode 1
-        versionName "0.1.0"
+        versionCode resolvedVersionCode
+        versionName resolvedVersionName
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         aaptOptions {
              // Files and dirs to omit from the packaged assets dir, modified to accommodate modern web apps.
@@ -27,7 +39,7 @@ android {
             if (keystorePropertiesFile.exists()) {
                 keyAlias keystoreProperties['keyAlias']
                 keyPassword keystoreProperties['keyPassword']
-                storeFile file(keystoreProperties['storeFile'])
+                storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
                 storePassword keystoreProperties['storePassword']
             }
         }