feat: Add VEX Status Chip component and integration tests for reachability drift detection

- Introduced `VexStatusChipComponent` to display VEX status with color coding and tooltips.
- Implemented integration tests for reachability drift detection, covering various scenarios including drift detection, determinism, and error handling.
- Enhanced `ScannerToSignalsReachabilityTests` with a null implementation of `ICallGraphSyncService` for better test isolation.
- Updated project references to include the new Reachability Drift library.

src/Scanner/StellaOps.Scanner.WebService/Domain/ScanId.cs

@@ -2,6 +2,11 @@ namespace StellaOps.Scanner.WebService.Domain;
 
 public readonly record struct ScanId(string Value)
 {
+    /// <summary>
+    /// Creates a new ScanId with a random GUID value.
+    /// </summary>
+    public static ScanId New() => new(Guid.NewGuid().ToString("D"));
+
     public override string ToString() => Value;
 
     public static bool TryParse(string? value, out ScanId scanId)