ci: make crowdin source synchronization deterministic

Upload and verify the checked-out English catalog before exporting translations so delayed webhooks cannot stall the scheduled workflow.

.github/workflows/crowdin-source-sync.yml

@@ -0,0 +1,55 @@
+name: Crowdin Source Sync
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [main]
+    paths:
+      - "client/src/locales/en.json"
+      - "crowdin.yml"
+
+permissions:
+  contents: read
+
+concurrency:
+  group: crowdin-synchronization
+  cancel-in-progress: false
+
+env:
+  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: "true"
+  NODE_VERSION: "26"
+  PNPM_VERSION: "11"
+
+jobs:
+  synchronize:
+    name: Synchronize English source
+    if: github.repository == 'bookorbit/bookorbit'
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Checkout main
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          ref: main
+
+      - name: Set up Node.js and pnpm
+        uses: ./.github/actions/setup-node-pnpm
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+          pnpm-version: ${{ env.PNPM_VERSION }}
+          prefetch: "true"
+
+      - name: Check synchronization credentials
+        env:
+          CROWDIN_TOKEN: ${{ secrets.CROWDIN_TOKEN }}
+        run: |
+          if [ -z "$CROWDIN_TOKEN" ]; then
+            echo "::error::CROWDIN_TOKEN is required."
+            exit 1
+          fi
+
+      - name: Synchronize English source
+        env:
+          CROWDIN_PROJECT_ID: ${{ vars.CROWDIN_PROJECT_ID }}
+          CROWDIN_TOKEN: ${{ secrets.CROWDIN_TOKEN }}
+        run: pnpm --filter client sync:crowdin-source

.github/workflows/crowdin-translations.yml

@@ -14,7 +14,7 @@ permissions:
   contents: read
 
 concurrency:
-  group: crowdin-translation-sync
+  group: crowdin-synchronization
   cancel-in-progress: false
 
 env: