fix(ci): explicitly checkout peptide-e2e in workflow_call context

When smoke.yml runs via workflow_call from another repo (peptide-repo-core,
peptide-starter-theme, etc.), GitHub Actions checks out the CALLER's repo
by default. The caller has no package-lock.json, so setup-node's npm cache
lookup fails with 'Some specified paths were not resolved'.

Fix: add repository/ref to the checkout step so we always fetch peptide-e2e
regardless of who calls the workflow. This ensures npm ci and Playwright
have the correct test code and dependency lockfile.

.github/workflows/smoke.yml

@@ -2,6 +2,10 @@
 #
 # Called by other repos via workflow_call as a deploy gate.
 # Secrets required: STAGING_WP_ADMIN_USER, STAGING_WP_ADMIN_PASSWORD
+#
+# IMPORTANT: When called via workflow_call, GitHub Actions checks out the
+# CALLER's repo by default, not peptide-e2e. We explicitly checkout
+# peptide-e2e so npm ci and Playwright have the correct test code + lock file.
 
 name: Smoke Tests (Staging)
 
@@ -32,8 +36,11 @@ jobs:
     timeout-minutes: 15
 
     steps:
-      - name: Checkout
+      - name: Checkout peptide-e2e (explicit — workflow_call defaults to caller repo)
         uses: actions/checkout@v4
+        with:
+          repository: peptiderepo/peptide-e2e
+          ref: main
 
       - name: Set up Node.js
         uses: actions/setup-node@v4