chore: gitignore local-only docs and remove from tracking

ProjectStructure.md, README.md, Roadmap.md, AI-CONTEXT.md, and docs/
are local development references — not needed in the repo.

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

Author: JasonHoku

.gitignore

@@ -5,4 +5,9 @@
 .claude_data/
 .claude/
 /.claude_data/
-/.claude/
+/.claude/
+AI-CONTEXT.md
+ProjectStructure.md
+README.md
+Roadmap.md
+docs/