Update CI to use clang-format 19

Upgrade from clang-format 16 to 19 to match modern formatting.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: bifurcation

.github/workflows/main_ci.yml

@@ -62,7 +62,7 @@ jobs:
     - name: Run clang-format style check for C/C++ programs
       uses: jidicula/clang-format-action@v4.11.0
       with:
-        clang-format-version: 16
+        clang-format-version: 19
         include-regex: '^\./(src|include|test|cmd|lib)/.*\.(cpp|h)$'
         fallback-style: 'Mozilla'