Update .env.examplefix: correct model ID in .env.example (claude-opus-4-0 -> claude-opus-4)

.env.example

@@ -10,7 +10,7 @@ XIMILAR_API_KEY=your-ximilar-api-key-here
 # Get yours at: https://console.anthropic.com/settings/keys
 ANTHROPIC_API_KEY=your-anthropic-api-key-here
 # Anthropic model for deck generation and coaching (Claude Opus recommended)
-ANTHROPIC_MODEL=claude-opus-4-0-20250514
+ANTHROPIC_MODEL=claude-opus-4-20250514
 # Coach chat provider: "local" (Ollama) or "anthropic" (Claude API)
 COACH_PROVIDER=anthropic