Move CI to Gitea: run-number offset, Cloudflare-only publishing

- plgVersionRunOffset=1000: stamped build number is run number + offset, so
  Gitea's restarted run counter cannot produce a versionCode below an
  installed one (GitHub reached prod 30, dev ~172). Tags and versionName use
  the same number.
- Drop the GitHub release steps; plg.wallacenet.ca is the only channel.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01JdMNbY5hLR7FjtfEE712xG

app/build.gradle.kts

@@ -16,6 +16,12 @@ val buildChannel = System.getenv("PLG_CHANNEL").orEmpty()
 val runNumber = (System.getenv("GITHUB_RUN_NUMBER") ?: "").toIntOrNull() ?: 0
 val stampVersion = buildChannel.isNotEmpty() && runNumber > 0
 
+// See plgVersionRunOffset in gradle.properties: the stamped build number is the
+// CI run number plus a permanent floor, so a counter that restarts on a new CI
+// host can never produce a lower versionCode than one already installed.
+val runOffset = (project.findProperty("plgVersionRunOffset") as String?)?.toIntOrNull() ?: 0
+val buildNumber = runNumber + runOffset
+
 // The version series, from gradle.properties. Both workflows read the same
 // property when they name a release tag, so the tag and the APK inside it
 // cannot disagree about which series they belong to.
@@ -51,10 +57,10 @@ android {
         // versionCode stays the run number and nothing else, so it keeps
         // climbing across a change of series: bumping 1.0 to 1.1 must not make
         // an update look like a downgrade to Android.
-        versionCode = if (stampVersion) runNumber else 1
+        versionCode = if (stampVersion) buildNumber else 1
         versionName = when {
-            stampVersion && buildChannel == "production" -> "$versionSeries.$runNumber"
-            stampVersion -> "$versionSeries.$runNumber-dev"
+            stampVersion && buildChannel == "production" -> "$versionSeries.$buildNumber"
+            stampVersion -> "$versionSeries.$buildNumber-dev"
             isDevBuild -> "$versionSeries.0-dev"
             else -> "$versionSeries.0"
         }