Add modernize-use-override to .clang-tidy and apply fixes across src/ and tests/: replace redundant virtual with override, annotate missing override on derived methods, and drop redundant virtual on already-overridden methods.
Add modernize-use-override to .clang-tidy and apply fixes across src/ and tests/: replace redundant virtual with override, annotate missing override on derived methods, and drop redundant virtual on already-overridden methods.