ci: add Gitea release workflow for AMD64/ARM64 binaries

Builds the Go binary on dedicated amd64/arm64 runners via Docker and
uploads both artifacts to the Gitea release.

.gitea/workflows/release.yml

@@ -0,0 +1,69 @@
+name: Release Binaries
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: false
+
+      matrix:
+        include:
+          - arch: amd64
+            platform: linux/amd64
+            image: golang:1.24-alpine
+            runner: linux-amd64
+            upx_install: "apk add --no-cache upx"
+          - arch: arm64
+            platform: linux/arm64
+            image: golang:1.24-alpine
+            runner: linux-arm64
+            upx_install: "apk add --no-cache upx zstd-static"
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build (${{ matrix.arch }})
+        run: |
+          set -o pipefail
+
+          # Crea il container senza avviarlo
+          CID=$(docker create \
+            --platform ${{ matrix.platform }} \
+            -w /src \
+            ${{ matrix.image }} \
+            sleep infinity)
+
+          # Copia i sorgenti dentro con docker cp (funziona anche in DinD)
+          docker cp "${{ github.workspace }}/." "$CID:/src"
+
+          # Avvia ed esegui la build
+          docker start "$CID"
+          docker exec "$CID" sh -c "
+            ${{ matrix.upx_install }}
+            export CGO_ENABLED=0
+            go build -trimpath -ldflags='-s -w' -o /src/dist/todotxt2remind .
+            upx /src/dist/todotxt2remind
+          " 2>&1 | cat
+
+          # Copia il binario fuori
+          docker cp "$CID:/src/dist/todotxt2remind" \
+            "${{ github.workspace }}/todotxt2remind-linux-${{ matrix.arch }}"
+
+          docker rm -f "$CID"
+
+      - name: Carica artefatto sulla release
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          RELEASE_ID: ${{ github.event.release.id }}
+        run: |
+          FILENAME="todotxt2remind-linux-${{ matrix.arch }}"
+          curl -s -X POST \
+            "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases/${RELEASE_ID}/assets?name=${FILENAME}" \
+            -H "Authorization: token ${TOKEN}" \
+            -H "Content-Type: application/octet-stream" \
+            --data-binary "@${FILENAME}"