Prefer system npm in deploy CI when portable node-gyp is broken.

Falls back to downloading Node only when host npm is unavailable, fixing npm ci failures on ladill-deploy-runner.

.gitea/workflows/deploy.yml

@@ -39,11 +39,17 @@ jobs:
             clone --depth 1 --single-branch --no-tags --branch "${{ gitea.ref_name }}" \
             "$REPO_URL" "$WORKSPACE"
 
-      - name: Setup Node.js
+      - name: Build frontend assets
         shell: bash {0}
         run: |
           set -Eeuo pipefail
-          if [ ! -x "$NODE_ROOT/bin/node" ]; then
+          cd "$WORKSPACE"
+          if command -v npm >/dev/null 2>&1 && npm -v >/dev/null 2>&1; then
+            NPM_BIN="$(command -v npm)"
+          elif [ -x "$NODE_ROOT/bin/npm" ]; then
+            export PATH="$NODE_ROOT/bin:$PATH"
+            NPM_BIN="$NODE_ROOT/bin/npm"
+          else
             rm -rf "$NODE_ROOT"
             mkdir -p "$NODE_ROOT"
             case "$(uname -m)" in
@@ -53,17 +59,12 @@ jobs:
             esac
             curl -fsSL "https://nodejs.org/download/release/v${NODE_VERSION}/node-v${NODE_VERSION}-linux-${NODE_ARCH}.tar.xz" \
               | tar -xJ --strip-components=1 -C "$NODE_ROOT"
+            export PATH="$NODE_ROOT/bin:$PATH"
+            NPM_BIN="$NODE_ROOT/bin/npm"
           fi
-          "$NODE_ROOT/bin/node" -v
+          "$NPM_BIN" ci --no-audit --no-fund
+          "$NPM_BIN" run build
 
-      - name: Build frontend assets
-        shell: bash {0}
-        run: |
-          set -Eeuo pipefail
-          cd "$WORKSPACE"
-          export PATH="$NODE_ROOT/bin:$PATH"
-          npm ci --no-audit --no-fund
-          npm run build
 
       - name: Build release archive
         shell: bash {0}