feat(cli): v1 agent contract with JSON errors, name resolution, dry runs and transfer fees

[StevenACZ]

Summary

Version 1.0.0 is a stable contract for scripts and agents.

• One JSON document on stdout for every command. Errors look like {ok:false,error:{code,message,hint,details}}.
• Exit codes: 0 ok, 1 failure, 2 usage, 3 auth, 4 not found, 5 rate limited.
• Lists: data is always an array, with a meta object alongside.
• Names or ids: accounts and categories accept either. An ambiguous or missing name returns the candidates.
• Safer writes:
  • --dry-run on money writes.
  • --yes for permanent deletes.
  • Balances are returned after every write.
• New commands:
  • overview
  • commands (the machine-readable command catalog)
  • transactions create-many
  • transfers create --fee (the fee is recorded atomically with the transfer)

Verification

• Checks pass: format, typecheck, lint, 213 tests, build, npm pack --dry-run.
• Read-only smoke against production: overview, lists, not-found and usage errors, and a transfer-with-fee dry run.