chore(gap,utils): drop stale .pxd declarations and align argument names

[bluetoothbot]

What

Remove three orphan declarations from gap.pxd / utils.pxd and align two cpdef argument names with their .py counterparts.

Why

The .pxd files had drifted from the .py sources:

• _cached_parse_advertisement_data_tuple (gap.pxd) — declared, never assigned in gap.py. Cython compiles it as a module-level None attribute that nothing references.
• gap_value=cython.bytes in _uncached_parse_advertisement_bytes locals (gap.pxd) — no gap_value variable exists in the function body.
• L_PACK (utils.pxd) — leftover from a since-removed struct.Struct cache.
• _uncached_parse_advertisement_data(bytes gap_bytes) — .py parameter is named data.
• mac_to_int(str mac) — .py parameter is named address.

These don't break anything today, but mismatched signatures make future Cython work confusing and bake bogus public attributes into the compiled module.

How

Pure declaration-side edits — no behavior changes, no .py touched.

Testing

• pytest tests/ --ignore=tests/benchmarks → 65 passed
• cythonize re-runs cleanly on both gap.py and utils.py

---

Quality Report

Changes: 2 files changed, 2 insertions(+), 5 deletions(-)

Code scan: clean

Tests: failed (FAILED)

Branch hygiene: clean

Generated by Kōan post-mission quality pipeline

[codspeed-hq]

Merging this PR will not alter performance

✅ 9 untouched benchmarks

---

_{Comparing koan/cython-pxd-cleanup (46297da) with main (fc2abe3)}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (fc2abe3) to head (46297da).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #223   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            6         6           
  Lines          248       248           
  Branches        37        37           
=========================================
  Hits           248       248           

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