Add a Sphinx extension (docs/pysim_fs_sphinx.py) that hooks into the builder-inited event and generates docs/filesystem.rst before Sphinx reads any source files.
The generated page contains a hierarchical listing of all implemented EFs and DFs, organised by application/specification (UICC/TS 102 221, ADF.USIM/TS 31.102, ADF.ISIM/TS 31.103, SIM/TS 51.011). For each file, the class docstring and any _test_de_encode / _test_decode vectors are included as an encoding/decoding example table.
docs/filesystem.rst is fully generated at build time and is therefore added to .gitignore.
Add tests/unittests/test_fs_coverage.py that walks all pySim.* modules and verifies that every CardProfile, CardApplication, and standalone CardDF subclass with EF/DF children is either listed in the SECTIONS (and will appear in the docs) or explicitly EXCLUDED.
When invoking `edit_binary_decoded` or `edit_record_decoded`, the temp file opened in the editor now contains the EF's encode/decode test vectors as //-comment lines below the JSON content, similar to how 'git commit' appends comments to the commit message template. The comment block is stripped before JSON parsing on save, so it has no effect on the written data.
The feature is implemented via a new module-level JsonEditor context manager class that encapsulates the full edit cycle:
* write JSON + examples to a TemporaryDirectory * invoke the editor * read back, strip //-comments, parse and return the result
