Enhance Torn Vault Tracker: Add documentation, improve exception handling, and update styles

- Updated .gitignore to exclude new directories and files.
- Enhanced config.php with detailed PHPDoc comments for better clarity.
- Refactored functions.php to include PHPDoc comments and improve code readability.
- Added custom exceptions in exceptions.php with detailed documentation.
- Improved utilities.php with better documentation and error handling.
- Updated index.php with structured comments and improved readability.
- Refined style.css for better visual consistency.
- Introduced phpcs.xml for coding style checks and standards enforcement.

.gitignore

@@ -3,3 +3,5 @@ backup/
 debug.log
 data/*
 !data/.gitkeep
+.claude/
+phpcs-results.txt