[aleksandr-miheichev]

Bump IPNetwork2 from 4.3.0 to 5.0.1, including the 5.x thread-safety and collection fixes. The existing Parse, Subtract, Supernet and Total usages need no API migration, and the package still provides a net10.0 asset.

Add 18 integration cases for generated TUN routes and Fake DNS pool sizes, covering IPv4/IPv6 separation, overlapping and duplicate exclusions, host-address boundaries, full-family exclusions, large IPv6 pools and invalid-range fallbacks.

Validation on source d8ebfa3 (A/B CI run):

• ServiceLib: 154/154 passed on Windows x64, Linux x64 and macOS ARM64 with both 4.3.0 and 5.0.1.
• WebAPI: 387/387 passed on Windows and Linux with both versions, using --maximum-parallel-tests 1.
• macOS WebAPI: 386/387 passed with both versions; the same existing InstanceLockOwnerCanBeReadWhileAnotherProcessHoldsTheLock test fails because reading the held lock's owner returns null. The CI run therefore has two failing baseline/candidate jobs.
• All 15 self-contained publishes passed: Avalonia and WebAPI for Windows/Linux/macOS x64 and ARM64, plus WPF for Windows x86/x64/ARM64.
• Local Windows baseline and candidate suites also passed. Negative controls confirmed that the route-exclusion and Fake DNS assertions reject intentional faults; production sources were restored afterward.

The isolated CI harness is kept on a separate fork branch and is excluded from this PR.