chore: update .gitignore for Claude Code, remove Aider

Replace Aider ignore patterns with Claude Code local config file.

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

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: djwhitt

.gitignore

@@ -16,8 +16,8 @@
 # macOS
 .DS_Store
 
-# Aider
-.aider*
+# Claude Code
+CLAUDE.local.md
 
 # Exceptions (keep these tracked)
 !/repos/.gitkeep