Add Pod specification and status visibility in UI for troubleshooting pending/failed Pod

# Summary

What change needs making?

Add the ability to view Pod specifications and status details directly from the Argo Workflows UI when Pods are in a Pending state or fail to start. Currently, when a Pod fails to start and remains in Pending status, users need to use kubectl commands to inspect the Pod spec and events to understand the root cause. Integrating this information into the UI would significantly improve the debugging experience.

## Use Cases

When would you use this?

- **Resource constraint debugging**: When Pods are stuck in Pending due to insufficient CPU/memory resources, users could quickly see the requested resources and current cluster capacity without switching to kubectl
- **Node selector/affinity issues**: When Pods cannot be scheduled due to node selector or affinity constraints, the Pod spec view would show the scheduling requirements that cannot be satisfied
- **Volume mounting problems**: When Pods fail to start due to PVC or ConfigMap/Secret mounting issues, users could inspect the volume configuration directly in the UI
- **Image pull failures**: When containers cannot start due to image pull errors, the Pod events and status would be visible alongside the image specifications
- **Permission and security context issues**: When Pods fail due to security policies or service account problems, the security context and service account details would be accessible for quick diagnosis
- **General workflow troubleshooting**: Any time a step in an Argo Workflow fails to execute, having immediate access to the underlying Pod information accelerates the debugging process without requiring command-line access

This feature would be particularly valuable for teams where not all users have direct kubectl access to the cluster, or in environments where quick visual debugging is preferred over command-line investigation.

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**Message from the maintainers**:

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The issue names no files, tests, or UI entry point. First locate the Argo Workflows UI components for workflow steps and inspect existing Pod-related data access; the scope, supported states, displayed fields, events, and tests still need to be defined before completion can be verified.

Written by the indexing model from the issue text.