Add Gitea restart workflow and link-style "Run again" for the public view

The server deployment cannot mount the Docker socket safely, so the web
view's button now opens the Gitea page for a workflow_dispatch workflow
that recreates the stack and replays the demo. Gitea handles who may run it.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.gitea/workflows/deploy.yml

@@ -28,6 +28,7 @@ jobs:
       - name: Deploy on the server's Docker daemon (viewer published on port 8099)
         env:
           VIEWER_BIND: "0.0.0.0"
+          RESTART_URL: https://git.my-rm.com/Robot-Market/mqtt-security-test/actions?workflow=restart.yml
           COMPOSE_PROJECT_NAME: crypto-interop-spike
         run: |
           set -eu

.gitea/workflows/restart.yml

@@ -0,0 +1,24 @@
+name: Restart demo
+# Replays the whole demo on the server without rebuilding anything. Run it from Gitea (Actions, then
+# "Run workflow"); only users with access to the repository can do that, which is why the public web
+# view has no restart button of its own. The web view's "Run again (via Gitea)" button opens this page.
+on:
+  workflow_dispatch:
+concurrency:
+  group: mqtt-security-test
+  cancel-in-progress: false
+jobs:
+  restart:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Recreate the stack (fresh broker, new run); images are reused, built only if missing
+        env:
+          VIEWER_BIND: "0.0.0.0"
+          RESTART_URL: https://git.my-rm.com/Robot-Market/mqtt-security-test/actions?workflow=restart.yml
+          COMPOSE_PROJECT_NAME: crypto-interop-spike
+        run: docker compose -f docker/compose.yaml up -d --force-recreate --remove-orphans
+      - name: Wait for the run and require every board check to pass
+        env:
+          COMPOSE_PROJECT_NAME: crypto-interop-spike
+        run: sh scripts/ci-verify.sh