Improve no wallet error message

[rolznz]

It doesn't say that a wallet connection hasn't been setup yet. It could be nice to recommend first-time setup first, then the current info somewhere else (type help for more options or something)

● Bash(npx -y @getalby/cli fetch-l402 \
        -u https://llm402.ai/v1/chat/completions \…)
  ⎿  Error: Exit code 1
     {
       "error": "No connection secret provided. Pass -c <secret or file path>, set NWC_URL, use
     --wallet-name <name>, or create ~/.alby-cli/connection-secret.key"
     }