Document chain configuration and environment setup for dApp projects

[timfong888]

Problem

CLI defaults to Calibration (314159) — good for dev, but no guidance for dApp .env setup or RPC endpoint configuration.

Details

• No mention of which RPC endpoints to use (SDK uses http() transport — which RPC?)
• getChain() from @filoz/synapse-core/chains is undocumented in skills
• Agents scaffolding a Next.js dApp don't know what env vars to set up

Ask

Add an environment setup section covering:

• Chain IDs (Calibration: 314159, Mainnet: 314)
• Recommended RPC URLs for each network
• Example .env / .env.local for Next.js projects
• How getChain() works and when to use it