fix .env.example (#13)

apps/web/.env.example

@@ -1,3 +1,4 @@
 # AI Gateway API Key (required for /api/generate endpoint)
-# Get your key from https://gateway.ai.cloudflare.com or your AI provider
+# Uses Vercel AI Gateway - automatically authenticated when deployed on Vercel
+# For local development, get your key from https://vercel.com/docs/ai/ai-sdk
 AI_GATEWAY_API_KEY=

examples/dashboard/.env.example

@@ -1,3 +1,4 @@
 # AI Gateway API Key (required for /api/generate endpoint)
-# Get your key from https://gateway.ai.cloudflare.com or your AI provider
+# Uses Vercel AI Gateway - automatically authenticated when deployed on Vercel
+# For local development, get your key from https://vercel.com/docs/ai/ai-sdk
 AI_GATEWAY_API_KEY=