chore: gitignore CLAUDE.local.md (per-contributor Claude overrides)

Author: luisguzman-adfa

.gitignore

@@ -11,3 +11,6 @@ Thumbs.db
 # pdf.js prebuilt dist (fetched at build time, not vendored) — ADFA-4708
 static/pdfjs/dist/
 controller/app/src/main/assets/kolibri_tree.jsonl
+
+# Local, per-contributor Claude overrides (never committed)
+CLAUDE.local.md