more detailed pod display in Tilt UI

Describe the Feature You Want

Display runtime pending reasons in the Tilt sidebar UI, e.g.:

• Waiting for new pods
• Waiting for pod X to initialize
• Waiting for pod X to pass readiness checks

Current Behavior

Right now, if a resource is pending, the Tilt UI will display the build status and a vague runtime status in the tooltip.

But it won't really give you detailed information on what it's looking for.

Why Do You Want This?

Easier to diagnose why a pod is failing.

Additional context
You can usually get this information from the CLI. For example, tilt get kd will tell you what pods tilt knows about and whether they're ready. But it won't give you this info in the UI.

There are some cases where you can see this data in the logs (like if you have a new deployment), but you won't always see it if you're attaching to an existing pod that's in crash reboot.

Start by comparing the Tilt UI's pending resource status with the information available from tilt get kd, focusing on how pod readiness and pending reasons are represented. Done means the sidebar shows whether it is waiting for new pods, pod initialization, or readiness checks, including the relevant pod when available.