Decide and Show Key Agent Metrics and Traces

[Shridhar-2205]

• Identify and agree on the core MCE metrics to track for agents
• Identify and agree on the key Grafana trace views to expose (for example: end-to-end request traces, slowest spans, error/exception traces, and dependency calls between services).
• Configure MCE and Grafana dashboards to surface only these agreed metrics and traces in a simple, default view suitable for most users.
• Wire the agents UI to these dashboards with “View metrics” and “View traces” links, ensuring they open the selected, agreed dashboards filtered for the current agent.

[jparello]

Defer this until we get an MCE or key metrics feature describing what to show