ci: fix Hugo install to match runner arch (arm64/amd64 auto-detect)

.gitea/workflows/deploy.yml

@@ -76,10 +76,17 @@ jobs:
       - name: Install Hugo Extended
         run: |
           set -euo pipefail
-          HUGO_TARBALL="hugo_extended_${HUGO_VERSION}_linux-amd64.tar.gz"
+          # Pick the tarball matching the runner CPU architecture (the runner
+          # image may be arm64, not amd64 — a mismatch gives "Exec format error").
+          case "$(uname -m)" in
+            x86_64|amd64)  HUGO_ARCH="linux-amd64" ;;
+            aarch64|arm64) HUGO_ARCH="linux-arm64" ;;
+            *) echo "unsupported arch: $(uname -m)"; exit 1 ;;
+          esac
+          HUGO_TARBALL="hugo_extended_${HUGO_VERSION}_${HUGO_ARCH}.tar.gz"
           URL="https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/${HUGO_TARBALL}"
-          echo "Downloading $URL"
-          curl -sSL --retry 3 -o /tmp/hugo.tar.gz "$URL"
+          echo "Runner arch $(uname -m) -> downloading $URL"
+          curl -fsSL --retry 3 -o /tmp/hugo.tar.gz "$URL"
           mkdir -p "$(dirname "$HUGO_BIN")"
           tar -xzf /tmp/hugo.tar.gz -C "$(dirname "$HUGO_BIN")" hugo
           "$HUGO_BIN" version