chore: add GitHub Actions workflows for deploying to GitHub Pages and PR previews

.github/workflows/gh-page-publish.yml

@@ -0,0 +1,51 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: .
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+          cache: true
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Run build_runner
+        run: flutter pub run build_runner build --delete-conflicting-outputs
+
+      - name: Run tests
+        run: flutter test
+
+      - name: Build web
+        run: flutter build web --base-href /pdf_signature/ --release -O4 --wasm
+
+      - name: Deploy to gh-pages branch
+        uses: peaceiris/actions-gh-pages@v4
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./build/web
+          publish_branch: gh-pages
+          exclude_assets: 'pr-preview/**'
+

.github/workflows/pr-preview.yml

@@ -0,0 +1,53 @@
+name: Deploy PR Preview
+
+on:
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - synchronize
+      - closed
+
+concurrency: preview-${{ github.ref }}
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  deploy-preview:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Flutter
+        if: github.event.action != 'closed'
+        uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+          cache: true
+
+      - name: Install dependencies
+        if: github.event.action != 'closed'
+        run: flutter pub get
+
+      - name: Run build_runner
+        if: github.event.action != 'closed'
+        run: flutter pub run build_runner build --delete-conflicting-outputs
+
+      - name: Run tests
+        if: github.event.action != 'closed'
+        run: flutter test
+
+      - name: Build web
+        if: github.event.action != 'closed'
+        run: flutter build web --base-href /pdf_signature/pr-preview/pr-${{ github.event.number }}/ --release -O4 --wasm
+
+      - name: Deploy preview
+        uses: rossjrw/pr-preview-action@v1
+        with:
+          source-dir: ./build/web/
+          preview-branch: gh-pages
+          umbrella-dir: pr-preview
+          action: auto