Add tests for SBOM generation determinism across multiple formats

- Created `StellaOps.TestKit.Tests` project for unit tests related to determinism.
- Implemented `DeterminismManifestTests` to validate deterministic output for canonical bytes and strings, file read/write operations, and error handling for invalid schema versions.
- Added `SbomDeterminismTests` to ensure identical inputs produce consistent SBOMs across SPDX 3.0.1 and CycloneDX 1.6/1.7 formats, including parallel execution tests.
- Updated project references in `StellaOps.Integration.Determinism` to include the new determinism testing library.

.gitea/workflows/test-lanes.yml

@@ -74,6 +74,48 @@ jobs:
           if-no-files-found: ignore
           retention-days: 7
 
+  # ===========================================================================
+  # Architecture Lane: Structural rule enforcement (PR-gating)
+  # ===========================================================================
+  architecture-tests:
+    name: Architecture Tests
+    runs-on: ubuntu-22.04
+    timeout-minutes: 10
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup .NET ${{ env.DOTNET_VERSION }}
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: ${{ env.DOTNET_VERSION }}
+          include-prerelease: true
+
+      - name: Restore architecture tests
+        run: dotnet restore tests/architecture/StellaOps.Architecture.Tests/StellaOps.Architecture.Tests.csproj
+
+      - name: Build architecture tests
+        run: dotnet build tests/architecture/StellaOps.Architecture.Tests/StellaOps.Architecture.Tests.csproj --configuration $BUILD_CONFIGURATION --no-restore
+
+      - name: Run Architecture tests
+        run: |
+          mkdir -p "$TEST_RESULTS_DIR"
+          dotnet test tests/architecture/StellaOps.Architecture.Tests/StellaOps.Architecture.Tests.csproj \
+            --configuration $BUILD_CONFIGURATION \
+            --no-build \
+            --logger "trx;LogFileName=architecture-tests.trx" \
+            --results-directory "$TEST_RESULTS_DIR" \
+            --verbosity normal
+
+      - name: Upload Architecture test results
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: architecture-test-results
+          path: ${{ env.TEST_RESULTS_DIR }}
+          if-no-files-found: ignore
+          retention-days: 7
+
   # ===========================================================================
   # Contract Lane: API contract stability tests (PR-gating)
   # ===========================================================================
@@ -290,7 +332,7 @@ jobs:
   test-summary:
     name: Test Results Summary
     runs-on: ubuntu-22.04
-    needs: [unit-tests, contract-tests, integration-tests, security-tests]
+    needs: [unit-tests, architecture-tests, contract-tests, integration-tests, security-tests]
     if: always()
     steps:
       - name: Download all test results
@@ -303,7 +345,7 @@ jobs:
           echo "## Test Lane Results" >> $GITHUB_STEP_SUMMARY
           echo "" >> $GITHUB_STEP_SUMMARY
 
-          for lane in unit contract integration security; do
+          for lane in unit architecture contract integration security; do
             result_dir="all-test-results/${lane}-test-results"
             if [ -d "$result_dir" ]; then
               echo "### ${lane^} Lane: ✅ Passed" >> $GITHUB_STEP_SUMMARY