Graphviz DOT Diagram Generator

Important: Use ```dot as the code fence identifier, NOT ```graphviz.

Quick Start: Choose digraph (directed) or graph (undirected) → Define nodes with attributes (shape, color, label) → Connect with -> or -- → Set layout (rankdir, spacing) → Wrap in ```dot fence. Default: top-to-bottom (rankdir=TB), cluster names must start with cluster_, use semicolons.

Critical Syntax Rules

Rule 1: Cluster Naming

❌ subgraph backend { }      → Won't render as box
✅ subgraph cluster_backend { }  → Must start with cluster_