feat: accept version facet

[svenrdz]

Closes #121

Add version the list of valid facets

---

TODO

• handle version facet in Query._from_detailed_dict

[svenrdz]

This change breaks esgpull search --detail N:

Traceback (most recent call last):
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/tui.py", line 180, in logging
    yield
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/cli/search.py", line 177, in search
    queries = esg.context.search_as_queries(
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/context.py", line 749, in search_as_queries
    return self._sync(coro)
           ^^^^^^^^^^^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/context.py", line 609, in _sync
    return sync(self._with_client(coro))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/utils.py", line 17, in sync
    result = asyncio.run(coro)
             ^^^^^^^^^^^^^^^^^
  File "/home/srodriguez/.local/share/uv/python/cpython-3.12.7-linux-x86_64-gnu/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/home/srodriguez/.local/share/uv/python/cpython-3.12.7-linux-x86_64-gnu/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/srodriguez/.local/share/uv/python/cpython-3.12.7-linux-x86_64-gnu/lib/python3.12/asyncio/base_events.py", line 687, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/context.py", line 598, in _with_client
    return await coro
           ^^^^^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/context.py", line 585, in _search_as_queries
    queries_result.process()
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/context.py", line 250, in process
    query = Query._from_detailed_dict(doc)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/models/query.py", line 437, in _from_detailed_dict
    result.selection[name] = values
    ~~~~~~~~~~~~~~~~^^^^^^
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/models/selection.py", line 119, in __setitem__
    setattr(self, name, value)
  File "/home/srodriguez/ws/test-pip-git/.venv/lib/python3.12/site-packages/esgpull/models/selection.py", line 58, in setter
    iter_values = enumerate(values)
                  ^^^^^^^^^^^^^^^^^
TypeError: 'int' object is not iterable