Expanded ignore list to ensure tool neutrality.

Author: RyanLamansky

.gitignore

@@ -258,4 +258,24 @@ paket-files/
 
 # Python Tools for Visual Studio (PTVS)
 __pycache__/
-*.pyc
+*.pyc
+
+# Don't want to be prescriptive about the user's development environment.
+.devcontainer/
+
+# The simplicity of this project structure enables AI tools to figure it out instantly.
+.claude/
+CLAUDE.md
+.codex/
+AGENTS.md
+.github/copilot-instructions.md
+.gemini/
+GEMINI.md
+.cursor/
+.cursorrules
+.aider*
+.windsurf/
+.windsurfrules
+
+# I've already seen one PR with scraps here, hoping to avoid it in the future.
+tmp/