ctest: api, conformance, roundtrip, metadata, stream, apng, symbols, link_test, fuzz smoke. Shared helpers live intests/test_common.{c,h}. Run with and without zlib-ng (-DQPNG_WITH_ZLIBNG=OFF), on GCC 16 and Clang 23.scripts/sanitize.sh: ASan+UBSan + ctest (SIMD and-DQPNG_NO_SIMD), mutation fuzzing; libFuzzer when clang is available.scripts/check_symbols.sh: no symbol outside the public API.- Encoder output for a given preset/filter/level must stay byte-identical to master across modern-C refactors unless a commit deliberately changes it.