refactor(examples): parameterize browse_tags.py, drop unittest.mock hack

[tommasofaedo]

Follow-up cleanup for examples/browse_tags.py (merged in #756).

Why

In your #756 review you flagged two blockers — the hardcoded PLC IP and the unittest.mock hack — and later said you'd pushed fixes for them. That cleanup commit didn't make it into the merge (#756 landed with commits: 1), so examples/browse_tags.py in master still has both. This PR applies them for real, and folds in a small correctness fix.

Changes

• argparse CLI — positional host, optional area letters, --port, --tls, --password. No more module-level PLC_HOST = "192.168.5.11".

  python browse_tags.py 192.168.5.11            # all areas, plaintext
  python browse_tags.py 192.168.5.11 --tls      # TLS-only PLCs (FW V4.1 "G2")
  python browse_tags.py 10.0.0.5 --tls I Q      # subset of areas
  

• Remove unittest.mock — the old code wrapped connect() in mock.patch.object(S7CommPlusConnection, "_post_auth_legitimation", ...). connect() already wraps the optional post-auth legitimation in a try/except that only logs a warning when it's skipped (no-password PLCs, or the plaintext V3 path where legitimation needs TLS), so the mock was redundant. Verified the browse works unchanged without it.
• I-area address fix — the 43 in the FDICT sample %I43.x is not the real tag address (only the bit digit is a literal); rebuild %I{ByteOffset}.{bit} so input_1 resolves to %I0.0 instead of %I43.0.
• PoC disclaimer in the module docstring (FDICT is firmware-family specific).

Tested on

Re-validated on a S7-1200 CPU 1212C, FW V4.1 ("G2"), over TLS 1.3 (mandatory on that unit — the FW V4.5 unit from #756 is no longer available to me, see #753):

$ python browse_tags.py <host> --tls
>> Area I  (RID=80) ... input_1   Bool  %I0.0  0  10
>> Area Q  (RID=81) ... output_1  Bool  %Q0.1  0   9
>> Area M  (RID=82) ... merker_1  Bool  %M0.2  0   9

All three project tags resolve to their exact TIA Portal addresses.

ruff format / ruff check clean. Example-only — no library code touched.

[gijzelaerr]

thanks! sorry merged that too quickly, you right