Summary: Support Mean Time to Resolve (MTTR) metrics for non-native incident tools

Description: Customers using third-party incident management tools (like PagerDuty or custom setups via GitOps/FluxCD) need a more robust way to populate the Mean Time to Resolve (MTTR) metric. Currently, even with integrations, the mapping of incident events to component metrics can be inconsistent.

Customer Goal: Automatically calculate MTTR based on incident lifecycle events pushed via REST API or third-party webhooks without requiring a native Jira Service Management link.