UI work to fill SBOM sourcing management gap. UI planning remaining functionality exposure. Work on CI/Tests stabilization

Introduces CGS determinism test runs to CI workflows for Windows, macOS, Linux, Alpine, and Debian, fulfilling CGS-008 cross-platform requirements. Updates local-ci scripts to support new smoke steps, test timeouts, progress intervals, and project slicing for improved test isolation and diagnostics.

src/SbomService/StellaOps.SbomService/Program.cs

@@ -91,6 +91,9 @@ builder.Services.AddSingleton<ISbomLineageGraphService, SbomLineageGraphService>
 // LIN-BE-028: Lineage compare service
 builder.Services.AddSingleton<ILineageCompareService, LineageCompareService>();
 
+// LIN-010: Lineage export service for evidence packs
+builder.Services.AddSingleton<ILineageExportService, LineageExportService>();
+
 // LIN-BE-023: Replay hash service
 builder.Services.AddSingleton<IReplayHashService, ReplayHashService>();
 
@@ -824,6 +827,41 @@ app.MapGet("/api/v1/lineage/{artifactDigest}/parents", async Task<IResult> (
     return Results.Ok(new { childDigest = artifactDigest.Trim(), parents });
 });
 
+app.MapPost("/api/v1/lineage/export", async Task<IResult> (
+    [FromServices] ILineageExportService exportService,
+    [FromBody] LineageExportRequest request,
+    CancellationToken cancellationToken) =>
+{
+    if (string.IsNullOrWhiteSpace(request.FromDigest) || string.IsNullOrWhiteSpace(request.ToDigest))
+    {
+        return Results.BadRequest(new { error = "fromDigest and toDigest are required" });
+    }
+
+    if (string.IsNullOrWhiteSpace(request.TenantId))
+    {
+        return Results.BadRequest(new { error = "tenantId is required" });
+    }
+
+    using var activity = SbomTracing.Source.StartActivity("lineage.export", ActivityKind.Server);
+    activity?.SetTag("tenant", request.TenantId);
+    activity?.SetTag("from_digest", request.FromDigest);
+    activity?.SetTag("to_digest", request.ToDigest);
+
+    var result = await exportService.ExportAsync(request, cancellationToken);
+
+    if (result is null)
+    {
+        return Results.StatusCode(500);
+    }
+
+    if (result.SizeBytes > 50 * 1024 * 1024)
+    {
+        return Results.StatusCode(413); // Payload Too Large
+    }
+
+    return Results.Ok(result);
+});
+
 // -----------------------------------------------------------------------------
 // Lineage Compare API (LIN-BE-028)
 // Sprint: SPRINT_20251228_007_BE_sbom_lineage_graph_ii