清理旧版残留，优化结构

.github/workflows/release.yml

@@ -128,6 +128,10 @@ jobs:
         run: CARGO_TARGET_DIR=target/agent cargo clippy --locked --manifest-path agent/Cargo.toml --all-targets -- -D warnings
       - name: Test backend
         run: CARGO_TARGET_DIR=target/backend cargo test --locked --manifest-path backend/Cargo.toml
+      - name: Test PostgreSQL backup and notification persistence
+        env:
+          NODEFLARE_TEST_POSTGRES_URL: postgres://nodeflare:SmokePostgresPassword123@127.0.0.1:5432/nodeflare_smoke
+        run: CARGO_TARGET_DIR=target/backend cargo test --locked --manifest-path backend/Cargo.toml postgres_restores_nullable_batches_and_pending_notifications -- --ignored
       - name: Test Agent
         run: CARGO_TARGET_DIR=target/agent cargo test --locked --manifest-path agent/Cargo.toml
       - name: Build Agent for smoke test