ci(dart-sdk-validation): detect drift (#1273)

.github/workflows/dart-sdk-validation.yaml

@@ -13,7 +13,50 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  openapi-drift:
+    name: Detect OpenAPI schema drift
+    runs-on: ubuntu-24.04
+    timeout-minutes: 15
+    steps:
+      - name: Checkout fluxer
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0
+        with:
+          persist-credentials: false
+
+      - name: Set up Rust toolchain (CI helpers)
+        uses: dtolnay/rust-toolchain@e97e2d8cc328f1b50210efc529dca0028893a2d9
+        with:
+          toolchain: "1.93.0"
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@0ebf47130e4866e96fce0953f49152a61190b271
+
+      - name: Install Node.js
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e
+        with:
+          node-version: '24'
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: >-
+          cargo run --locked --quiet --manifest-path tools/ci/Cargo.toml -- ci
+          --step install_dependencies
+
+      - name: Generate OpenAPI schemas
+        run: pnpm openapi:generate
+
+      - name: Validate OpenAPI schemas
+        run: pnpm openapi:validate
+
+      - name: Check drift of OpenAPI schemas
+        run: |
+          if ! git diff --exit-code -- fluxer_api/src/api/openapi/openapi.json fluxer_admin/openapi-admin.json; then
+            echo "::error::OpenAPI schemas are outdated."
+            exit 1
+          fi
+
   validate:
+    name: Validate Dart SDK generation
     runs-on: ubuntu-latest
     steps:
       - name: Check changed files