UI DX: make MetaMask connect + network switching more reliable

[snissn]

Problem

Generated UIs can fail to switch networks in MetaMask with a vague message like:

Wrong network… (An error occurred when attempting to switch chain.)

This is especially common when the user is currently on a non-local chain (e.g. chainId 314159) and the app expects Anvil (31337).

Fix

Improve the wallet connect + network switch flow:

• Connect first (eth_requestAccounts) before attempting a network switch. Some wallets behave more reliably when already connected.
• Best-effort add + switch fallback: if wallet_switchEthereumChain fails, attempt wallet_addEthereumChain and retry switching.
• Actionable errors:
  • Detect user-rejected requests and tell them to approve the prompt.
  • When possible, include the expected chain name/id and the RPC URL to add in MetaMask.

How to test

1. Run pnpm th dev apps/example/job-board.schema.json.
2. In MetaMask, switch to another network (e.g. a testnet).
3. In the UI, try creating a record.
4. Expected: the UI connects the wallet, then prompts to add/switch to Anvil (31337); errors are now actionable if rejected.