Nanodesu! 1.0.1

A maintenance release: the tool now ships with a test suite and continuous
integration, plus two robustness fixes.

Added

Test suite — 16 tests covering archive parsing, the extract → build
round trip, --pyc header handling, contents-directory placement, PYZ
extraction and the error paths. Synthetic archives keep the whole suite under
a second, so no sample executable is needed:
```
python -m unittest discover -s test -v
```
Dedicated regression tests cover the three format details that silently
produce a broken repack: lowercase z marking a PYZ archive, PYZ item type
0 being an ordinary module, and headers prepended by --pyc being stripped
again on repack.
Continuous integration — .github/workflows/tests.yml runs the suite on
Linux and Windows across Python 3.9, 3.12, 3.13 and 3.14, byte-compiles both
modules, self-tests the character canvas and smoke-tests the CLI.

PYZ extraction could overwrite a module. When a module and a package
claimed the same file path inside a PYZ archive (for example utils and
utils.sub), the second one silently replaced the first. The extractor now
detects the collision, writes the later module under a flattened name, and
reports what it did.
Cleaner failures. A missing path or a directory passed where an archive
was expected now prints a one-line message and exits with status 1, instead
of showing a Python traceback.

16/16 tests pass on Python 3.9, 3.12, 3.13 and 3.14.
Self-check on a 138.8 MB onefile build: 836 entries extracted, all verified,
and unpack → repack → unpack still reproduces every file byte for byte.
The tool extracts and repacks itself: nanodesu.exe (62 entries) unpacks,
repacks, passes verification, and the repacked binary still runs.

No dependencies beyond Python 3.9+.

pip install .                                  # provides the `nanodesu` command
python nanodesu.py --help                      # or run it directly

The attached nanodesu.exe is a standalone 64-bit Windows build for
convenience.