[wangyinz]

Fixes #825

This PR removes shared mutable default state from both miniSEED matchers and copies every caller-provided iterable before adding channel-only attributes.

Validation includes an independent agent review, MongoDB 8.0.29 adjacent regressions, an exact baseline-red suite, input immutability checks for lists/tuples/iterators, Black, py_compile, Ruff, and diff checks.

This PR is ready for human review. It must not be merged automatically.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.20%. Comparing base (83034b9) to head (f708b5b).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #964      +/-   ##
==========================================
+ Coverage   72.14%   72.20%   +0.05%     
==========================================
  Files         182      182              
  Lines       36089    36090       +1     
  Branches     2532     2532              
==========================================
+ Hits        26037    26057      +20     
+ Misses       9146     9127      -19     
  Partials      906      906              

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