v0.4.3

• ci.yml, ci-cell.yml — added Linux TinyCC (tcc) CI cell and install-smoke row via apt-get install tcc; examples skipped for the tcc cell;
• CMakeLists.txt — when CMAKE_C_COMPILER_ID is TinyCC, use CMAKE_C_STANDARD 99 (distro tcc lacks ISO C17);
• run_all_unit_tests.sh, run_all_scratch_tests.sh, run_all_examples.sh — restore execute bits after CI artifact download (so find/test -x discovery works); fail if --unit-only finds no programs;