[FEATURE]: add a bounded wait tool for asynchronous work #24888

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Add a built-in wait tool that lets an agent pause the current turn for a bounded amount of time, optionally returning early when an external condition becomes true.

This helps with workflows where the model needs to continue in the same chat after an asynchronous event, such as a download finishing, a dev server becoming ready, a background process exiting, or a log file showing a completion pattern. Today the agent has to burn shell slots, ask the user to come back, or repeatedly poll through ad hoc commands.

Suggested behavior:

• fixed bounded waits with a visible reason
• cancellable waits that respect the existing abort signal
• optional early-return conditions for file readiness, URL readiness, process exit, and log pattern matching
• progress metadata so the UI can show what the agent is waiting on
• hard caps on wait duration and polling intervals to avoid runaway waits