chore: add ROADMAP.md to gitignore

Keep local planning document out of version control

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: raaymax

.gitignore

@@ -1,4 +1,5 @@
 /target
 CLAUDE.md
 AGENTS.md
+ROADMAP.md
 *.log