fix(website): migrate website to pnpm + fix MDX/dep issues blocking deploy

.github/workflows/deploy-website.yml

@@ -33,38 +33,24 @@ jobs:
           # most pages without a last-updated date).
           fetch-depth: 0
 
+      # pnpm via corepack — the version is pinned by the `packageManager` field
+      # in the root package.json, so CI uses the same pnpm as local dev. The
+      # website is a pnpm workspace member (pnpm-workspace.yaml), so one
+      # `pnpm install` at the root installs every package including the website.
+      - uses: pnpm/action-setup@v4
+
       - name: Setup Node
         uses: actions/setup-node@v6
         with:
           node-version: 22
-          cache: npm
-          cache-dependency-path: website/package-lock.json
+          cache: pnpm
 
       - name: Install dependencies
-        working-directory: website
-        run: |
-          # npm ci intermittently crashes with "Exit handler never called!"
-          # (a known npm bug under runner memory pressure). Retry up to 3 times,
-          # falling back to `npm install` which is more tolerant of lockfile
-          # state. --ignore-scripts avoids running postinstall (prepare-source
-          # runs the build steps explicitly below).
-          for i in 1 2 3; do
-            if npm ci --ignore-scripts; then break; fi
-            echo "npm ci attempt $i failed; retrying in 10s…"
-            sleep 10
-            if [ "$i" = "3" ]; then
-              echo "npm ci failed 3 times; falling back to npm install"
-              npm install --ignore-scripts
-            fi
-          done
-
-      - name: Generate MDX source
-        working-directory: website
-        run: npm run prepare-source
+        run: pnpm install --frozen-lockfile
 
       - name: Build
         working-directory: website
-        run: npm run build
+        run: pnpm run build
         env:
           TASKFLOW_BASE_PATH: /taskflow