feat(dev): add pre-commit hooks for ruff, eslint, and prettier (#2525)

* feat(dev): add pre-commit hooks for ruff, eslint, and prettier

* fix: use local uv-based ruff hooks and uv run for pre-commit install

Agent-Logs-Url: https://github.com/bytedance/deer-flow/sessions/a1e34cc5-0d4b-4400-9e6a-e687d964ff1e

Co-authored-by: WillemJiang <219644+WillemJiang@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

.pre-commit-config.yaml

@@ -0,0 +1,33 @@
+repos:
+  # Backend: ruff lint + format via uv (uses the same ruff version as backend deps)
+  - repo: local
+    hooks:
+      - id: ruff
+        name: ruff lint
+        entry: bash -c 'cd backend && uv run ruff check --fix "${@/#backend\//}"' --
+        language: system
+        types_or: [python]
+        files: ^backend/
+      - id: ruff-format
+        name: ruff format
+        entry: bash -c 'cd backend && uv run ruff format "${@/#backend\//}"' --
+        language: system
+        types_or: [python]
+        files: ^backend/
+
+  # Frontend: eslint + prettier (must run from frontend/ for node_modules resolution)
+  - repo: local
+    hooks:
+      - id: frontend-eslint
+        name: eslint (frontend)
+        entry: bash -c 'cd frontend && npx eslint --fix "${@/#frontend\//}"' --
+        language: system
+        types_or: [javascript, tsx, ts]
+        files: ^frontend/
+
+      - id: frontend-prettier
+        name: prettier (frontend)
+        entry: bash -c 'cd frontend && npx prettier --write "${@/#frontend\//}"' --
+        language: system
+        files: ^frontend/
+        types_or: [javascript, tsx, ts, json, css]

CONTRIBUTING.md

@@ -166,7 +166,7 @@ Required tools:
 
 1. **Configure the application** (same as Docker setup above)
 
-2. **Install dependencies**:
+2. **Install dependencies** (this also sets up pre-commit hooks):
    ```bash
    make install
    ```

Makefile

@@ -23,7 +23,7 @@ help:
 	@echo "  make config          - Generate local config files (aborts if config already exists)"
 	@echo "  make config-upgrade  - Merge new fields from config.example.yaml into config.yaml"
 	@echo "  make check           - Check if all required tools are installed"
-	@echo "  make install         - Install all dependencies (frontend + backend)"
+	@echo "  make install         - Install all dependencies (frontend + backend + pre-commit hooks)"
 	@echo "  make setup-sandbox   - Pre-pull sandbox container image (recommended)"
 	@echo "  make dev             - Start all services in development mode (with hot-reloading)"
 	@echo "  make dev-pro         - Start in dev + Gateway mode (experimental, no LangGraph server)"
@@ -73,6 +73,8 @@ install:
 	@cd backend && uv sync
 	@echo "Installing frontend dependencies..."
 	@cd frontend && pnpm install
+	@echo "Installing pre-commit hooks..."
+	@$(BACKEND_UV_RUN) --with pre-commit pre-commit install
 	@echo "✓ All dependencies installed"
 	@echo ""
 	@echo "=========================================="

README.md

@@ -264,7 +264,7 @@ On Windows, run the local development flow from Git Bash. Native `cmd.exe` and P
 
 2. **Install dependencies**:
    ```bash
-   make install  # Install backend + frontend dependencies
+   make install  # Install backend + frontend dependencies + pre-commit hooks
    ```
 
 3. **(Optional) Pre-pull sandbox image**: