fix: replace complex mdformat regex with simple exclude pattern

The complex negative lookahead regex was still causing issues in CI
environments. Replaced it with the simpler and more reliable approach
using separate 'files' and 'exclude' patterns.

Changes:
- files: '\.md$' (matches all markdown files)
- exclude: '^(\.venv|venv|__pycache__|\.git|node_modules|\.egg-info|\.pytest_cache|\.mypy_cache|\.ruff_cache|dist|build)/'

This approach is more readable, easier to maintain, and works consistently
across different environments.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: SimplicityGuy

.pre-commit-config.yaml

@@ -35,7 +35,8 @@ repos:
           - mdformat-black==0.1.1
           - mdformat-gfm==0.4.1
           - mdformat-tables==1.0.0
-        files: '^(?!.*(^|/)(\.venv|venv|__pycache__|\.git|node_modules|\.egg-info|\.pytest_cache|\.mypy_cache|\.ruff_cache|dist|build)/).*\.md$'
+        files: '\.md$'
+        exclude: '^(\.venv|venv|__pycache__|\.git|node_modules|\.egg-info|\.pytest_cache|\.mypy_cache|\.ruff_cache|dist|build)/'
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: db90487f48a9dd992d243ef63c156eaffddeaf28  # frozen: v0.12.11