fix(ci): guard install step to verify sfw is installed

Fails fast with a clear error if sfw binary is not set up before
pnpm install runs.

Author: jdalton

.github/workflows/setup-and-install.yml

@@ -163,4 +163,9 @@ jobs:
       - name: Install dependencies
         shell: bash
         working-directory: ${{ inputs.working-directory }}
-        run: pnpm install --loglevel error
+        run: |
+          if [ -z "$SFW_BIN" ] || [ ! -x "$SFW_BIN" ]; then
+            echo "Error: sfw is not set up — run the setup action first" >&2
+            exit 1
+          fi
+          pnpm install --loglevel error