fix: upgrade deprecated GitHub Actions and remove unwrap

- actions/upload-artifact v3→v4 (v3 deprecated, blocks all CI jobs)
- actions/setup-python v4→v5
- actions/download-artifact v3→v4
- github/codeql-action/upload-sarif v2→v3
- codecov/codecov-action v3→v4
- peaceiris/actions-gh-pages v3→v4
- actions/create-release v1→softprops/action-gh-release v2
- Gate Slack notifications on webhook secret presence
- Fix k8s compliance check to skip when k8s/ dir missing
- Replace unwrap() with match in info_nce_loss_mined

Co-Authored-By: claude-flow <ruv@ruv.net>

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
         fetch-depth: 0
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ env.PYTHON_VERSION }}
         cache: 'pip'
@@ -54,7 +54,7 @@ jobs:
       continue-on-error: true
 
     - name: Upload security reports
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       if: always()
       with:
         name: security-reports
@@ -98,7 +98,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
         cache: 'pip'
@@ -126,14 +126,14 @@ jobs:
         pytest tests/integration/ -v --junitxml=integration-junit.xml
 
     - name: Upload coverage reports
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
         file: ./coverage.xml
         flags: unittests
         name: codecov-umbrella
 
     - name: Upload test results
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       if: always()
       with:
         name: test-results-${{ matrix.python-version }}
@@ -153,7 +153,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ env.PYTHON_VERSION }}
         cache: 'pip'
@@ -174,7 +174,7 @@ jobs:
         locust -f tests/performance/locustfile.py --headless --users 50 --spawn-rate 5 --run-time 60s --host http://localhost:8000
 
     - name: Upload performance results
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: performance-results
         path: locust_report.html
@@ -236,7 +236,7 @@ jobs:
         output: 'trivy-results.sarif'
 
     - name: Upload Trivy scan results
-      uses: github/codeql-action/upload-sarif@v2
+      uses: github/codeql-action/upload-sarif@v3
       if: always()
       with:
         sarif_file: 'trivy-results.sarif'
@@ -252,7 +252,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ env.PYTHON_VERSION }}
         cache: 'pip'
@@ -272,7 +272,7 @@ jobs:
         "
 
     - name: Deploy to GitHub Pages
-      uses: peaceiris/actions-gh-pages@v3
+      uses: peaceiris/actions-gh-pages@v4
       with:
         github_token: ${{ secrets.GITHUB_TOKEN }}
         publish_dir: ./docs
@@ -286,7 +286,7 @@ jobs:
     if: always()
     steps:
     - name: Notify Slack on success
-      if: ${{ needs.code-quality.result == 'success' && needs.test.result == 'success' && needs.docker-build.result == 'success' }}
+      if: ${{ secrets.SLACK_WEBHOOK_URL != '' && needs.code-quality.result == 'success' && needs.test.result == 'success' && needs.docker-build.result == 'success' }}
       uses: 8398a7/action-slack@v3
       with:
         status: success
@@ -296,7 +296,7 @@ jobs:
         SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
 
     - name: Notify Slack on failure
-      if: ${{ needs.code-quality.result == 'failure' || needs.test.result == 'failure' || needs.docker-build.result == 'failure' }}
+      if: ${{ secrets.SLACK_WEBHOOK_URL != '' && (needs.code-quality.result == 'failure' || needs.test.result == 'failure' || needs.docker-build.result == 'failure') }}
       uses: 8398a7/action-slack@v3
       with:
         status: failure
@@ -307,18 +307,16 @@ jobs:
 
     - name: Create GitHub Release
       if: github.ref == 'refs/heads/main' && needs.docker-build.result == 'success'
-      uses: actions/create-release@v1
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      uses: softprops/action-gh-release@v2
       with:
         tag_name: v${{ github.run_number }}
-        release_name: Release v${{ github.run_number }}
+        name: Release v${{ github.run_number }}
         body: |
           Automated release from CI pipeline
-          
+
           **Changes:**
           ${{ github.event.head_commit.message }}
-          
+
           **Docker Image:**
           `${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ github.sha }}`
         draft: false