ci: update artifact upload actions to use standard upload-artifact action

.gitea/actions/local-ci-build/action.yml

@@ -282,7 +282,7 @@ runs:
     # ── Upload build artifacts on success ─────────────────────────────────────
     - name: Upload artifacts
       if: success() && inputs.skip-artifact != 'true'
-      uses: https://gitea.emulab.it/Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
+      uses: actions/upload-artifact@v4
       with:
         name: ${{ steps.invoke-ci.outputs.artifact-name }}
         path: ${{ steps.invoke-ci.outputs.artifact-path }}\
@@ -292,7 +292,7 @@ runs:
     # ── Upload diagnostic logs on failure ─────────────────────────────────────
     - name: Upload diagnostic logs on failure
       if: failure()
-      uses: https://gitea.emulab.it/Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
+      uses: actions/upload-artifact@v4
       with:
         name: build-logs-${{ github.sha }}
         path: ${{ steps.invoke-ci.outputs.artifact-path }}\*.log

.gitea/workflows/self-test.yml

@@ -22,7 +22,7 @@ jobs:
   smoke-windows:
     runs-on: windows-build
     steps:
-      - uses: Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
+      - uses: https://gitea.emulab.it/Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
         with:
           # Trivial no-op build: write a marker file to the CI output directory.
           # The Windows build VM maps C:\CI\output as the artifact source.
@@ -35,7 +35,7 @@ jobs:
   smoke-linux:
     runs-on: linux-build
     steps:
-      - uses: Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
+      - uses: https://gitea.emulab.it/Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
         with:
           # Trivial no-op build: write a marker file to the CI output directory.
           # The Linux build VM uses /opt/ci/output as the artifact source.