fix: remove committed node_modules symlink and harden gitignore (finos#2708)

Author: rocketstack-matt

.gitignore

@@ -31,7 +31,9 @@ docs/contributing.md
 **/.vscode**/
 /.vscode/settings.json
 
-node_modules/
+# No trailing slash: also ignores a `node_modules` symlink (git stores symlinks
+# as files, so a trailing-slash pattern would not match them) — see issue #2707
+node_modules
 **/dist/
 **/.vscode-test/
 **/out/