add gitlab dashboard trigger workflow (#1153)

Add workflow to trigger dashboard build.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Chores**
* Added a GitHub Actions workflow “Build Dashboard” to manually trigger
the dashboard build pipeline.
* Runs on ubuntu-latest and triggers the main branch pipeline with
secure credentials.
* Provides clear success/failure logging and halts on errors to ensure
reliable builds.
* Improves operational control by enabling on-demand dashboard builds
without code changes.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Signed-off-by: Jared Wilber <jwilber@nvidia.com>

Author: jwilber

.github/workflows/build-dashboard.yml

@@ -0,0 +1,24 @@
+name: Build Dashboard
+
+on:
+  workflow_dispatch:
+
+jobs:
+  trigger:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Trigger GitLab dashboard pipeline
+        env:
+          GITLAB_TRIGGER_TOKEN: ${{ secrets.GITLAB_TRIGGER_TOKEN }}
+          GITLAB_PROJECT_ID_DASHBOARDS: "130554"
+        run: |
+          echo "Triggering GitLab dashboard pipeline (main)..."
+          if curl -fsS -X POST \
+              -F "token=${GITLAB_TRIGGER_TOKEN}" \
+              -F "ref=main" \
+              "https://gitlab-master.nvidia.com/api/v4/projects/${GITLAB_PROJECT_ID_DASHBOARDS}/trigger/pipeline" >/dev/null; then
+            echo "✓ Triggered GitLab dashboard pipeline."
+          else
+            echo "✗ Failed to trigger GitLab dashboard pipeline." >&2
+            exit 1
+          fi