[.gitignore] Ignore .claude and .gemini in subdirectories

Currently .claude and .gemini are only ignored ignored in the root of
the repo. Developers might conceivable run these tools in project
specific subdirectories, in which case these should be ignored as well.

Author: JDevlieghere

.gitignore

@@ -54,9 +54,9 @@ autoconf/autom4te.cache
 /cmake-build*
 # Coding assistants' stuff
 /CLAUDE.md
-/.claude/
+.claude/
 /GEMINI.md
-/.gemini/
+.gemini/
 
 #==============================================================================#
 # Directories to ignore (do not add trailing '/'s, they skip symlinks).