fix(profile): tolerate malformed base64 titles

Author: snowyukitty

lib/features/profile/data/profile_parser.dart

@@ -357,7 +357,11 @@ class ProfileParser {
 
         if (headers['profile-title'] case final String titleHeader when name.isBlank) {
           if (titleHeader.startsWith("base64:")) {
-            name = utf8.decode(base64.decode(titleHeader.replaceFirst("base64:", "")));
+            try {
+              name = utf8.decode(base64.decode(titleHeader.replaceFirst("base64:", "")));
+            } on FormatException {
+              // Ignore malformed optional metadata and continue through the fallback hierarchy.
+            }
           } else {
             name = titleHeader.trim();
           }

test/features/profile/data/profile_parser_test.dart

@@ -160,6 +160,26 @@ void main() {
       });
     });
 
+    test("Should fall back when the base64 title is malformed", () {
+      expectRemote(
+        parseRemoteWithHeaders(
+          {"profile-title": "base64:not valid base64!!"},
+          url: "https://example.com/config#fallback",
+        ),
+        (rp) => expect(rp.name, equals("fallback")),
+      );
+    });
+
+    test("Should fall back when the base64 title is invalid UTF-8", () {
+      expectRemote(
+        parseRemoteWithHeaders(
+          {"profile-title": "base64:/w=="},
+          url: "https://example.com/config#fallback",
+        ),
+        (rp) => expect(rp.name, equals("fallback")),
+      );
+    });
+
     test("Should keep web page and support urls without subscription-userinfo", () {
       final headers = <String, List<String>>{
         "profile-title": ["title"],