test: add automated readonly smoke command matrix

[cinnabarhorse]

Summary

• adds scripts/smoke-readonly.sh to run an end-to-end read-only command matrix against Base + Goldsky
• matrix covers:
  • profile/policy/rpc/signer read commands
  • subgraph generic commands (list, check, query)
  • Baazaar subgraph wrappers (active, mine, get --verify-onchain)
  • GBM wrappers (active, mine, bids, bids-mine, get --verify-onchain)
  • onchain read path (onchain call) and baazaar read parity path
• script bootstraps a readonly profile automatically in temp AGCLI_HOME
• script dynamically discovers listing/auction IDs from active queries and falls back to known-safe IDs if needed
• wires script into npm:
  • npm run smoke:readonly
• updates README with usage notes and AG_BIN override to validate installed binaries

Test Plan

• npm run typecheck
• npm test
• npm run smoke:readonly
• AG_BIN=/tmp/aavegotchi-cli-global/bin/ag npm run smoke:readonly

Preview

• N/A (CLI repository; no Vercel app)