chore: Update copyright notices to end with 2026

[Copilot]

All files with copyright notices now have their year ranges updated to end with 2026.

Changes

• Updated 125 files from 2025-2025 to 2025-2026
• Updated 2 files from 2024-2025 to 2024-2026

All 133 copyright notices across Python source files, tests, and documentation now reflect the current year.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Update copyright notice with 2026 in every file</issue_title>
<issue_description>All files that currently have a copyright notice at the top should have a copyright range ending in 2026 (i.e. ...-2026).</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Update copyright notice with 2026 in every file #259

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (ba2cc71) to head (a07665b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #260   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           53        53           
  Lines         3098      3098           
=========================================
  Hits          3098      3098           

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