Direct activation of flights in scenarios 'utm.nominal_planning'

[mickmis]

In the following conditions (list attempts to be exhaustive, but might not be) the USS qualifier will directly activate a flight with planning it beforehand:

• scenario ConflictHigherPriority, case Attempt to activate flight in conflict: Flight 1 may be attempted to be activated directly without being planned first if the USS previously removed planned Flight 1 after the previous rejected modification attempt

• scenario ConflictHigherPriority, case Modify activated flight with pre-existing conflict: Flight 1 may be activated directly without being planned first if the USS previously removed planned Flight 1 after the previous rejected modification attempt

• scenario ConflictEqualPriorityNotPermitted, case Attempt to activate flight into conflict: Flight 1 is attempted to be activated directly without being planned first

• scenario ConflictEqualPriorityNotPermitted, case Attempt to modify activated flight into conflict: Flight 1c may be activated directly without being planned first if the USS previously removed planned Flight 1c after the previous rejected modification attempt

• scenario ConflictEqualPriorityNotPermitted, case Modify activated flight with pre-existing conflict: Flight 1 may be activated directly without being planned first if the USS qualifier previously deleted activated Flight 1c

There is a first issue with that: the DSS does not support yet direct activation of an operational intent, see interuss/dss#1294

Then, it is an open question for me whether it is reasonable to require USSs to support this operation. I.e., should the USS qualifier accepts a `NotSupported' response?

This issue has been discussed at the 2025-11-04 InterUSS weekly meeting.