chore: gitignore agent instruction files synced from mermaid-ops

These files (CLAUDE.md, AGENTS.md, assistant/, .claude/skills/,
package-level CLAUDE.md files) are synced from the mermaid-ops
control plane via /sync and should not be committed to this repo.

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

Author: knsv

.gitignore

@@ -53,3 +53,11 @@ vite.config.ts.timestamp-*
 
 # autogenereated by langium-cli
 generated/
+
+# Agent instruction files (synced from mermaid-ops via /sync, not committed here)
+/CLAUDE.md
+/AGENTS.md
+/assistant/
+/.claude/skills/
+packages/mermaid/src/diagrams/CLAUDE.md
+packages/parser/CLAUDE.md