ci: attempt to deploy the demo to github pages

.github/workflows/demo.yml

@@ -0,0 +1,54 @@
+# Simple workflow for deploying static content to GitHub Pages
+name: Deploy static content to Pages
+
+on:
+  # Runs on pushes targeting the default branch
+  push:
+    branches: ["main"]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  # Single deploy job since we're just deploying
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: '.tool-versions'
+      - uses: erlef/setup-beam@v1
+        with:
+          version-file: '.tool-versions'
+          version-type: 'strict'
+      - name: Build demo
+        run: ./bin/build-demo.sh
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          # Upload entire repository
+          path: './demo/out'
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4
+

bin/build-demo.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env sh
+
+# Move to the correct folder
+cd demo/
+set -x
+
+# Do a build
+gleam build
+
+# Move all the static files into place
+for f in index.html build/dev/javascript/lustre_ui/priv/static/lustre-ui.css; do
+	mkdir -p ./out/$(dirname $f)
+	cp ./$f ./out/$f
+done
+
+# Bundle all our JavaScript together
+mkdir -p ./priv/static
+./build/.lustre/bin/esbuild ./priv/static/commonmark_demo.mjs --bundle --outfile=./out/priv/static/commonmark_demo.mjs

demo/.gitignore

@@ -3,3 +3,4 @@
 /build
 /priv
 erl_crash.dump
+/out

demo/src/commonmark_demo/message.gleam

@@ -1,6 +1,5 @@
 import commonmark
 import commonmark_demo/model.{type Model, Model}
-import gleam/io
 import lustre/effect
 
 pub type Msg {