Add Forgejo CI smoke workflow for migration pilot

Probes host (self-hosted) and container (ubuntu-latest) runner labels on
railiance01-build-01 as part of CUST-WP-0054 forge routing validation.

.forgejo/workflows/ci-smoke.yaml

@@ -0,0 +1,27 @@
+name: CI Smoke
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  host-smoke:
+    runs-on: self-hosted
+    steps:
+      - name: Routing probe (host runner)
+        run: |
+          set -eu
+          echo "repository=${GITHUB_REPOSITORY:-unknown}"
+          echo "sha=${GITHUB_SHA:-unknown}"
+          echo "runner=${RUNNER_NAME:-unknown}"
+          uname -a
+
+  container-smoke:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Routing probe (container label)
+        run: |
+          set -eu
+          echo "glas-harness container-smoke ok"