chore: add graphify knowledge graph outputs

Add generated knowledge graph (538 nodes, 664 edges) for codebase
navigation. Outputs are committed for portability across devices;
cache and cost tracking are gitignored.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -236,3 +236,7 @@ playwright-report/
 # Claude Code
 .claude/
 
+# graphify (cache only — outputs are committed)
+graphify-out/cache/
+graphify-out/cost.json
+