feat(02-04): create bin/lib/claude.js as Claude runtime module boundary

bin/lib/claude.js

@@ -0,0 +1,11 @@
+'use strict';
+
+// Claude Code is the "base case" runtime — no content conversion needed.
+// Claude-specific install behavior (commands/gsd/ structure, settings.json hooks,
+// statusline support) is handled by the orchestrator in install.js since it is
+// the default code path shared with Gemini.
+//
+// This module exists as the architectural boundary for the Claude runtime,
+// ready for Claude-specific logic if needed in the future.
+
+module.exports = {};