K2GO-377 chore(backup): the user's backup file takes the product name too

The suggested filename kept the iiab-oa_ prefix the built artifacts just left behind, so the app
would have written backups under one name while the bucket held another. It is only ever a
suggestion for the SAF picker: nothing reads it back, and a restore identifies an archive by the
manifest inside it, so backups already written under the old name keep restoring unchanged.

Author: luisguzman-adfa

controller/app/src/main/java/org/iiab/controller/backup/domain/BackupEngine.java

@@ -29,14 +29,20 @@ public final class BackupEngine {
 
     private BackupEngine() {}
 
-    /** Suggested external filename: {@code iiab-oa_YYYY.DDD_<epochSecs>_<arch>.tar.gz}. */
+    /**
+     * Suggested external filename: {@code k2go_YYYY.DDD_<epochSecs>_<arch>.tar.gz}.
+     *
+     * <p>K2GO-377: the prefix follows the built rootfs artifacts onto the product's own name. It is
+     * only ever a suggestion for the SAF picker — nothing reads it back, and a restore identifies an
+     * archive by the manifest inside it, so backups written under the old name keep working.
+     */
     public static String suggestedFileName(Context ctx) {
         java.util.Calendar c = java.util.Calendar.getInstance();
         int year = c.get(java.util.Calendar.YEAR);
         int day = c.get(java.util.Calendar.DAY_OF_YEAR);
         String abi = org.iiab.controller.deploy.data.RootfsManifest.appAbiId();
         String arch = abi != null && abi.contains("64") ? "aarch64" : "armhf";
-        return String.format(java.util.Locale.US, "iiab-oa_%04d.%03d_%d_%s.tar.gz",
+        return String.format(java.util.Locale.US, "k2go_%04d.%03d_%d_%s.tar.gz",
                 year, day, System.currentTimeMillis() / 1000L, arch);
     }
 

controller/app/src/test/java/org/iiab/controller/deploy/domain/ExtractProgressTest.java

@@ -32,8 +32,8 @@ public void ordinaryNamesAreStillShown() {
     public void shortHexLikeWordsAreNotMistakenForDigests() {
         assertEquals("deadbeef.conf", ExtractProgress.fileLabel("etc/deadbeef.conf"));
         assertEquals("facade.png", ExtractProgress.fileLabel("share/facade.png"));
-        assertEquals("iiab-oa_2026.224_standard.tar.gz",
-                ExtractProgress.fileLabel("downloads/iiab-oa_2026.224_standard.tar.gz"));
+        assertEquals("k2go_2026.224_standard.tar.gz",
+                ExtractProgress.fileLabel("downloads/k2go_2026.224_standard.tar.gz"));
     }
 
     /** Fails open: a name we cannot classify is shown, never hidden on a guess. */

controller/app/src/test/java/org/iiab/controller/download/domain/MetalinkFileTest.java

@@ -21,15 +21,15 @@ public class MetalinkFileTest {
     private static final String META4 =
             "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
             + "<metalink xmlns=\"urn:ietf:params:xml:ns:metalink\" version=\"4.0\">\n"
-            + "  <file name=\"iiab-oa_2026.192_standard_17dd521_arm64-v8a.tar.gz\">\n"
+            + "  <file name=\"k2go_2026.192_standard_17dd521_arm64-v8a.tar.gz\">\n"
             + "    <size>1453144579</size>\n"
             + "    <hash type=\"sha-256\">" + FILE_HASH + "</hash>\n"
             + "    <pieces type=\"sha-256\" length=\"1048576\">\n"
             + "      <hash type=\"sha-256\">" + FIRST_PIECE_HASH + "</hash>\n"
             + "      <hash type=\"sha-256\">67c19c9e0509ff1aaeb104fce7498f53f02052acb18a241409b6d58c9c114142</hash>\n"
             + "    </pieces>\n"
-            + "    <url>https://iiab.switnet.org/android/rootfs/iiab-oa_2026.192_standard_17dd521_arm64-v8a.tar.gz</url>\n"
-            + "    <url>https://mirror2.example.org/iiab-oa_2026.192_standard_17dd521_arm64-v8a.tar.gz</url>\n"
+            + "    <url>https://pub-d64c885cef6c42db8c7925144d73d0ee.r2.dev/k2go_2026.192_standard_17dd521_arm64-v8a.tar.gz</url>\n"
+            + "    <url>https://mirror2.example.org/k2go_2026.192_standard_17dd521_arm64-v8a.tar.gz</url>\n"
             + "  </file>\n"
             + "</metalink>\n";
 
@@ -40,7 +40,7 @@ private MetalinkFile parse() throws Exception {
     }
 
     @Test public void parsesFileName() throws Exception {
-        assertEquals("iiab-oa_2026.192_standard_17dd521_arm64-v8a.tar.gz", parse().fileName());
+        assertEquals("k2go_2026.192_standard_17dd521_arm64-v8a.tar.gz", parse().fileName());
     }
 
     @Test public void parsesSize() throws Exception {