Package NSC debug symbols and source artifact

[AnastaZIuk]

Summary

• install Debug executable PDBs through nbl_install_exe_spec, which makes the NSCExecutables package include nsc_d.pdb
• add a tools/nsc regression test that verifies the preinstalled Debug nsc PDB exists
• publish a separate source artifact for every CI run using a fast rg --files -uu manifest, which captures tracked and generated source-like files while skipping .git and the heavy examples_tests/media payload

Validation

• cmake --preset user-configure-dynamic-msvc
• cmake --build build/dynamic --target nsc --config Debug -- /m
• ctest --test-dir build/dynamic/tools/nsc -C Debug --output-on-failure -R "^(NBL_NSC_INSTALL_RUNTIMES_TEST|NBL_NSC_INSTALL_EXECUTABLES_TEST|NBL_NSC_INSTALL_EXECUTABLES_PDB_TEST|NBL_NSC_COMPILE_AT_EXE_CWD_TEST|NBL_NSC_COMPILE_CUSTOM_CWD_TEST|NBL_NSC_DUMP_BUILD_INFO_TEST|NBL_NSC_SELF_TEST_UNMOUNT_BUILTINS)$"
• local source artifact manifest timing on an equivalent build/dynamic tree: about 0.18 s