feat: add workflow to check for missing i18n keys in translation files

.github/workflows/i18n-check.yaml

@@ -0,0 +1,57 @@
+name: Check Missing i18n Keys
+
+on:
+  push:
+    paths:
+      - "src/locales/en.json"
+      - "src/locales/*.json"
+      - ".github/workflows/i18n-check.yml"
+  workflow_dispatch:
+
+jobs:
+  check-i18n:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install jq
+        run: sudo apt-get install -y jq
+
+      - name: Check missing i18n keys
+        id: check-missing
+        run: |
+          mkdir -p i18n-missing
+          EN_KEYS=$(jq -r 'keys[]' src/locales/en.json | sort)
+          for file in src/locales/*.json; do
+            [ "$file" = "src/locales/en.json" ] && continue
+            LANG=$(basename "$file" .json)
+            jq -r 'keys[]' "$file" | sort > tmp_keys.txt
+            comm -23 <(echo "$EN_KEYS") tmp_keys.txt > i18n-missing/$LANG.txt || true
+            if [ -s i18n-missing/$LANG.txt ]; then
+              echo "Missing keys in $LANG:"
+              cat i18n-missing/$LANG.txt
+            fi
+          done
+
+      - name: Create PR if missing keys found
+        uses: peter-evans/create-pull-request@v6
+        if: |
+          always() && (hashFiles('i18n-missing/*.txt') != '')
+        with:
+          commit-message: "chore(i18n): report missing translation keys"
+          title: "chore(i18n): report missing translation keys"
+          body: |
+            The following language files are missing keys compared to en.json:
+
+            ${{ steps.check-missing.outputs.summary }}
+
+            Each file in `i18n-missing/` lists the missing keys for that language.
+          branch: i18n/missing-keys-report
+          add-paths: |
+            i18n-missing/*.txt