chore: consolidate essential fixes and add pre-commit hooks

- Add pre-commit configuration with ruff and black
- Fix lint CI job to use uv tool install instead of sync
- Add essential LlamaIndex dependencies to leann-core

Co-Authored-By: Yichuan Wang <73766326+yichuan-w@users.noreply.github.com>

.github/workflows/build-reusable.yml

@@ -26,17 +26,17 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v4
       
-      - name: Install dependencies
+      - name: Install ruff
         run: |
-          uv sync --dev
+          uv tool install ruff
       
       - name: Run ruff check
         run: |
-          uv run ruff check .
+          ruff check .
       
       - name: Run ruff format check
         run: |
-          uv run ruff format --check .
+          ruff format --check .
 
   build:
     needs: lint