chore: add ignore/ directory to .gitignore

The ignore/ directory contains test data files that should not be
committed to the repository.

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

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

Author: Hamish Downer

.gitignore

@@ -1,5 +1,8 @@
 docs/source
 
+# Project-specific ignores
+ignore/
+
 # From https://raw.githubusercontent.com/github/gitignore/main/Python.gitignore
 
 # Byte-compiled / optimized / DLL files