Cloud sessions: --environment parses names and ids, and --cloud accepts more ways of passing the task

What

These changes affect starting a cloud session, which runs Claude Code on remote machines instead of your own, with --cloud and --environment.

• --environment is now parsed as a pool, an id (starting env_) or a name. Only a pool id actually works so far: anything else still returns the error that --environment expects a self-hosted environment id (ccpool_...).
• A cloud run without the interactive screen now resolves an environment query, if one is given, before creating the session. If that fails it stops with an error. If it succeeds it adds a notice, unless the chosen environment moved.
• The --cloud hint text and flag are now chosen when an environment query is given, not only when a pool is.
• When --cloud is given with no value, the task can now come from the prompt you passed separately, such as piped input or a positional argument. The --cloud requires a description error and the message about --cloud not also taking piped input are kept.
• The non-interactive error asking you to drop --cloud/--remote with a description now applies only when the environment is a pool.

Why

More ways of calling claude --cloud are accepted without the interactive screen. Choosing an environment by name or env_ id is not usable yet, so keep using ccpool_ ids for now.