style: Add braces to all control flow statements

Standardize code style by adding explicit braces to all single-statement
  control flow blocks (if, else, for, while) across the entire codebase.

  Also documents the InsertBraces clang-format option (requires v15+) for
  future automated enforcement.

libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp

@@ -125,8 +125,9 @@ QStringList CardDatabaseLoader::collectCustomDatabasePaths() const
                     QDirIterator::Subdirectories | QDirIterator::FollowSymlinks);
 
     QStringList paths;
-    while (it.hasNext())
+    while (it.hasNext()) {
         paths << it.next();
+    }
     paths.sort();
     return paths;
 }