Workflow lifecycle events + resource instance duration tracking

- Add WorkflowLifecycleEvent + StepMetric to tools/workflow_lifecycle.go
- Add WORKFLOW_STARTED_EVENT, WORKFLOW_STEP_DONE_EVENT, WORKFLOW_DONE_EVENT NATS methods
- ResourceInstance.UpdateAverageDuration for AverageDurationS running average
- Support Steps recap in WORKFLOW_DONE_EVENT for catch-up by oc-scheduler/oc-catalog

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/workflow_lifecycle.go

@@ -0,0 +1,33 @@
+package tools
+
+import "time"
+
+// StepMetric carries the outcome of one Argo step node as observed by oc-monitord.
+// Embedded in WorkflowLifecycleEvent.Steps for the WORKFLOW_DONE_EVENT recap.
+type StepMetric struct {
+	BookingID string     `json:"booking_id"`
+	State     int        `json:"state"`
+	RealStart *time.Time `json:"real_start,omitempty"`
+	RealEnd   *time.Time `json:"real_end,omitempty"`
+}
+
+// WorkflowLifecycleEvent is the NATS payload emitted by oc-monitord on
+// WORKFLOW_STARTED_EVENT, WORKFLOW_STEP_DONE_EVENT, and WORKFLOW_DONE_EVENT.
+//
+//   - ExecutionID  : WorkflowExecution UUID (used by oc-scheduler to update state)
+//   - ExecutionsID : run-group ID shared by all bookings of the same run
+//   - BookingID    : non-empty only for WORKFLOW_STEP_DONE_EVENT
+//   - State        : target state (enum index: SUCCESS=3, FAILURE=4, STARTED=2, …)
+//   - RealStart    : actual start timestamp recorded by Argo (nil if unknown)
+//   - RealEnd      : actual end timestamp recorded by Argo (nil for STARTED events)
+//   - Steps        : non-nil only for WORKFLOW_DONE_EVENT — full recap of every step
+//     so oc-scheduler and oc-catalog can catch up if they missed STEP_DONE events
+type WorkflowLifecycleEvent struct {
+	ExecutionID  string       `json:"execution_id"`
+	ExecutionsID string       `json:"executions_id"`
+	BookingID    string       `json:"booking_id,omitempty"`
+	State        int          `json:"state"`
+	RealStart    *time.Time   `json:"real_start,omitempty"`
+	RealEnd      *time.Time   `json:"real_end,omitempty"`
+	Steps        []StepMetric `json:"steps,omitempty"`
+}