fix(ci): include pnpm-lock.yaml in sparse-checkouts for docs preview/teardown

actions/setup-node@v6 with cache: pnpm needs the lockfile present to compute
the cache key, even if the job never runs pnpm install. Without it the
preview deploy + teardown fail with "Dependencies lock file is not found".

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: FelixTJDietrich

.github/workflows/cd-docs-teardown.yml

@@ -28,6 +28,7 @@ jobs:
           sparse-checkout: |
             .github/actions/setup-pnpm-node
             .node-version
+            pnpm-lock.yaml
           sparse-checkout-cone-mode: false
 
       - name: Setup pnpm + Node.js

.github/workflows/cd-docs.yml

@@ -96,9 +96,11 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
+          # Need: composite action, Node version, lockfile (for actions/setup-node cache key).
           sparse-checkout: |
             .github/actions/setup-pnpm-node
             .node-version
+            pnpm-lock.yaml
           sparse-checkout-cone-mode: false
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4
         with: