ci: add Firefox AMO + GitHub release workflow

.github/workflows/deploy.yml

@@ -0,0 +1,63 @@
+name: Build & Release Firefox Addon
+
+on:
+  push:
+    branches: [main, beta]  # dev is ignored
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    outputs:
+      version: ${{ steps.version.outputs.version }}
+
+    steps:
+      # 1️⃣ Checkout code
+      - uses: actions/checkout@v4
+
+      # 2️⃣ Install dependencies
+      - name: Install deps
+        run: npm install -g web-ext jq
+
+      # 3️⃣ Auto version bump (numeric only)
+      - name: Generate version
+        id: version
+        run: |
+          BASE=$(jq -r .version manifest.json)
+          VERSION="${BASE}.${GITHUB_RUN_NUMBER}"
+          echo "version=$VERSION" >> $GITHUB_OUTPUT
+          jq ".version = \"$VERSION\"" manifest.json > tmp.json
+          mv tmp.json manifest.json
+
+      # 4️⃣ Build XPI
+      - name: Build extension
+        run: web-ext build
+
+      # 5️⃣ Get built XPI path
+      - name: Get XPI path
+        id: xpi
+        run: |
+          FILE=$(ls web-ext-artifacts/*.xpi | head -n 1)
+          echo "file=$FILE" >> $GITHUB_OUTPUT
+
+      # 6️⃣ GitHub Release (both main and beta)
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: v${{ steps.version.outputs.version }}
+          name: v${{ steps.version.outputs.version }}
+          files: ${{ steps.xpi.outputs.file }}
+          prerelease: ${{ github.ref == 'refs/heads/beta' }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      # 7️⃣ AMO deploy (main only)
+      - name: Sign & Upload to AMO
+        if: github.ref == 'refs/heads/main'
+        run: |
+          web-ext sign \
+            --api-key ${{ secrets.FIREFOX_API_KEY }} \
+            --api-secret ${{ secrets.FIREFOX_API_SECRET }} \
+            --source-dir . \
+            --artifacts-dir web-ext-artifacts \
+            --channel unlisted