chore(gitignore): ignore graphify-out/ generated directory

graphify-out/ contains the knowledge graph, AST/semantic cache, and
HTML report — all regenerated by /graphify. No value in tracking them.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -51,6 +51,11 @@ $RECYCLE.BIN/
 # AI/strumenti locali
 .claude/
 
+# Graphify generated output (knowledge graph, AST/semantic cache)
+graphify-out/
+
 # Python bytecode
 __pycache__/
 *.pyc
+
+cache/