Add latest compiler coverage to CI

[justsmth]

Description of changes:

Updates CI to cover GCC 16 and Clang 22 across x86-64, ARM64, macOS FIPS, and native Windows jobs. The pedantic matrix now tests the two most recent GCC and Clang releases.

Call-outs:

The ARM64 Clang 22 job moves from Ubuntu 25.04 to Ubuntu 26.04. clang-tidy is updated to version 21 rather than 22 because that is the latest version supported by the current clang-tidy-review action.

Testing:

Validated the modified workflows with YAML parsing, matrix assertions, git diff --check, and editor diagnostics. The new compiler combinations will be exercised by CI.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[github-actions]

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Please review before merging.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.20%. Comparing base (f01746a) to head (4dee9a3).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3406   +/-   ##
=======================================
  Coverage   78.20%   78.20%           
=======================================
  Files         695      695           
  Lines      124220   124220           
  Branches    17263    17261    -2     
=======================================
+ Hits        97148    97151    +3     
+ Misses      26151    26147    -4     
- Partials      921      922    +1     

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