CI: set up Node in nightly + release jobs (fix npm not found turning main red)

.github/workflows/nightly.yml

@@ -142,6 +142,17 @@ jobs:
           set -euo pipefail
           ./scripts/select-nightly-xcodes.sh
 
+      # Provide node/npm explicitly. The build/sign/notarize job can land on a
+      # self-hosted macOS runner (the iOS-CI minis match the same label) that has
+      # no npm on PATH, so `npm install --global create-dmg` failed with
+      # "npm: command not found" and turned nightly red. setup-node makes the job
+      # self-sufficient on any runner instead of assuming a preinstalled npm.
+      - name: Set up Node
+        if: needs.decide.outputs.should_publish != 'true' || steps.current_head_prebuild.outputs.still_current == 'true'
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version: "20"
+
       - name: Install build deps
         if: needs.decide.outputs.should_publish != 'true' || steps.current_head_prebuild.outputs.still_current == 'true'
         run: |

.github/workflows/release.yml

@@ -152,6 +152,15 @@ jobs:
           xcodebuild -version
           xcrun --sdk macosx --show-sdk-path
 
+      # Same self-sufficiency as nightly: a self-hosted macOS runner may lack npm
+      # on PATH, which breaks the pinned create-dmg install below. setup-node
+      # guarantees node/npm regardless of which runner picks up the job.
+      - name: Set up Node
+        if: steps.guard_release_assets.outputs.skip_all != 'true'
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version: "20"
+
       - name: Install build deps
         if: steps.guard_release_assets.outputs.skip_all != 'true'
         run: |