[docs] add summary of virtual states into the operation_order.md

Author: Michal Tichák

docs/handbook/operation_order.md

@@ -102,3 +102,19 @@ This is the order of actions happening at a healthy end of run.
 - `after_STOP_ACTIVITY` hooks with positive weights (incl. 0) are executed:
   - `ccdb.RunStop()` at `0`
   - `bookkeeping.UpdateRunStop()`, `bookkeeping.UpdateEnv()` at `+100`
+
+## Virtual (manager-driven) states and transitions
+
+State **PENDING** and transitions **TEARDOWN**, and **DESTROY** lie outside the core FSM in `environment.go` and are driven by the Manager. See [core/environment/manager.go](https://github.com/AliceO2Group/Control/blob/master/core/environment/manager.go) for details.
+
+### State PENDING
+
+Before the FSM enters `STANDBY`, the Manager drives the initial creation steps by emitting `Ev_EnvironmentEvent` messages (`Transition: CREATE`) for both `before_CREATE` (running hooks) and `CREATE` (loading workflow).
+
+### Transition TEARDOWN
+
+When the FSM is in `RUNNING`, the Manager records both `run_end_time_ms` and `run_end_completion_time_ms` and emits message `Ev_RunEvent` with content (`Transition: TEARDOWN`, `OpStatus_STARTED`) for each of timestamps.
+
+### Transition DESTROY
+
+The Manager’s `TeardownEnvironment(...)` drives a four‑step `Ev_EnvironmentEvent` sequence (`before_DESTROY`, `leave_<state>`, `DESTROY`, `after_DESTROY`) on `topic.Environment` to release tasks, run hooks, and finalize teardown.