Improve Enroute Conflict Management in Cruise Phase#1729

Currently, during the cruise phase, ATC appears to ignore traffic conflicts with other aircraft. This significantly reduces realism, especially in dense airspace.

ATC should actively manage enroute separation by issuing appropriate instructions, such as:

Heading adjustments (vectors)
Altitude changes (climb/descend)
Temporary altitude restrictions in high-traffic areas

These instructions should be dynamically based on surrounding traffic to maintain proper separation, similar to real-world ATC operations.

Mach speed adjustments (until separation is achieved or for sequencing for the STAR)