Enable entire-graph

AGENTS.md

@@ -0,0 +1,6 @@
+<!-- entire-graph:begin -->
+This repo has the entire-graph code graph installed. Before exploring code with
+grep/find/whole-file reads, read .entire/graph-agent.md — resolution-first guidance
+for using graph retrieval, focused source inspection, and verification.
+@.entire/graph-agent.md
+<!-- entire-graph:end -->