feat: add wait support for instance and tool

[jo-hnny]

Summary

• add a shared stable-state waiter for Instance and Tool lifecycle commands
• expose --wait on Instance create/get/pause/resume/update and Tool create/fork/get/update
• poll explicit transitional states every 5 seconds with a 10-minute timeout, returning the final GET resource once a known stable state is reached
• reject unknown statuses with WAIT_UNKNOWN_STATUS and preserve mutation response metadata

State handling

• Instance transitional states: STARTING, PAUSING, STOPPING
• Instance stable states: RUNNING, PAUSED, STOPPED, FAILED, STARTING_FAILED, STOPPING_FAILED, PAUSE_FAILED, RESUME_FAILED
• Tool transitional states: CREATING, DELETING
• Tool stable states: ACTIVE, FAILED, ISOLATED

Failure-like stable states are returned as the settled resource. --wait indicates that the resource has left a transitional state; it does not reinterpret the backend lifecycle result.

Delete and list commands intentionally do not expose --wait. For delete, the command does not have a final resource to return consistently after deletion.

Validation

• env GOCACHE=/private/tmp/ags-cli-gocache go test ./...
• command help and generated-schema characterization tests cover where --wait is exposed and excluded

Closes #72