Version 0.31, build 31

One change since 0.30, android!154: the unsealed-send and changed-address
notices. versionCode and versionName move together, as the comment above
them requires.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/build.gradle.kts

@@ -43,8 +43,8 @@ android {
         // is a label. Code 24 with name 0.24 closes it by skipping the name
         // 0.23, which costs nothing because a name is a label and may skip.
         // From here they move together and match: 25 with 0.25, 26 with 0.26.
-        versionCode = 30
-        versionName = "0.30"
+        versionCode = 31
+        versionName = "0.31"
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }