Staging example in environments.toml can't build (guess_the_number has no id) #277

Summary

The staging section of the template's environments.toml enables a client for guess_the_number but gives it no id (environments.toml#L78-L86):

[staging.contracts]
guess_the_number = { client = true, constructor_args = "--admin me", after_deploy = "reset" }

In staging and production the CLI never deploys anything. It only generates bindings for contracts that have an id, and fails otherwise (handle_production_contracts, cli clients.rs#L666-L682). So STELLAR_SCAFFOLD_ENV=staging stellar scaffold build --build-clients stops with:

⛔ ️An ID must be set for a contract in production or staging. E.g. <name>.id = C...

That error only comes after the account step has already generated testnet-user and funded it on testnet through friendbot.

constructor_args and after_deploy are also silently ignored outside development and testing. The line therefore suggests a capability that doesn't exist, and --admin me refers to a development-only identity.

Suggested fix

Comment the entry out, add an id placeholder, and explain how to get one:

# Deploy first (e.g. `stellar registry deploy …` or `stellar contract deploy …`), then paste the ID:
# guess_the_number = { client = true, id = "C..." }

Acceptance criteria

STELLAR_SCAFFOLD_ENV=staging stellar scaffold build --build-clients in a fresh project doesn't fail because of the template's own example entry.

Related: stellar-scaffold/cli#159

Found by reading the template (88bd964) and the CLI's handle_production_contracts (cli 0f385de); not run against testnet.