- Fix ignored return value in TxtReaderActivity
- Remove unused variables across multiple files
- Add const correctness to DictionaryMargins and EpubReaderActivity
- Replace inefficient substr patterns with resize+append
- Use STL algorithms (find_if, any_of, copy_if, transform) where applicable
- Remove dead sync placeholder code in EpubReaderChapterSelectionActivity
- Add cppcheck suppression for ValueFlow analysis limitation
Resolves all low, medium, and high severity cppcheck defects.
