chore: ignore entire docs/ folder (not in git)

.gitignore

@@ -46,8 +46,8 @@ _output/
 # Reference materials (not in git, static copies)
 ref/
 
-# Documentation PDFs (not in git, use external storage)
-docs/*.pdf
+# Documentation folder (not in git, external storage)
+docs/
 
 # Testing
 .pytest_cache/