ci(doc-deploy): fix pnpm cache setup and upgrade Node to 22

The doc-deploy workflow failed with "Unable to locate executable file:
pnpm" because actions/setup-node (with cache: pnpm) ran before pnpm was
installed. Reorder the steps so pnpm/action-setup runs first, matching
the order already used in doc-build-test.yml. Also pin pnpm to v10 and
upgrade Node.js from 20 (deprecated on GitHub Actions runners) to 22
in both doc workflows to clear the deprecation warning.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

.github/workflows/doc-build-test.yml

@@ -43,7 +43,7 @@ jobs:
           version: 10
       - uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: '22'
           cache: pnpm
           cache-dependency-path: home/pnpm-lock.yaml
       - uses: actions/setup-python@v4

.github/workflows/doc-deploy.yml

@@ -47,20 +47,20 @@ jobs:
         with:
           fetch-depth: 0
 
+      # Setup pnpm (must run before setup-node so the pnpm cache can be configured)
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
       # Setup Node.js environment
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: '22'
           cache: pnpm
           cache-dependency-path: home/pnpm-lock.yaml
 
-      # Setup pnpm
-      - name: Setup pnpm
-        uses: pnpm/action-setup@v4
-        with:
-          version: latest
-
       # Install dependencies in home directory
       - name: Install Dependencies
         working-directory: home