feat(api): implement notebook management CRUD endpoints

Implement Sprint 1: Notebook Management CRUD

- Add NotebookService with full CRUD operations
- Add POST /api/v1/notebooks (create notebook)
- Add GET /api/v1/notebooks (list with pagination)
- Add GET /api/v1/notebooks/{id} (get by ID)
- Add PATCH /api/v1/notebooks/{id} (partial update)
- Add DELETE /api/v1/notebooks/{id} (delete)
- Add Pydantic models for requests/responses
- Add custom exceptions (ValidationError, NotFoundError, NotebookLMError)
- Add comprehensive unit tests (31 tests, 97% coverage)
- Add API integration tests (26 tests)
- Fix router prefix duplication
- Fix JSON serialization in error responses

BREAKING CHANGE: None

.github/workflows/ci.yml

@@ -0,0 +1,62 @@
+name: CI
+
+on:
+  push:
+    branches: [ main, develop ]
+  pull_request:
+    branches: [ main, develop ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.10', '3.11', '3.12']
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v3
+
+    - name: Set up Python
+      run: uv python install ${{ matrix.python-version }}
+
+    - name: Install dependencies
+      run: uv sync --extra dev
+
+    - name: Run pre-commit
+      run: uv run pre-commit run --all-files
+
+    - name: Run tests
+      run: uv run pytest --cov=src/notebooklm_agent --cov-report=xml
+
+    - name: Upload coverage
+      uses: codecov/codecov-action@v3
+      with:
+        file: ./coverage.xml
+        fail_ci_if_error: false
+
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v3
+
+    - name: Set up Python
+      run: uv python install 3.11
+
+    - name: Install dependencies
+      run: uv sync --extra dev
+
+    - name: Lint with ruff
+      run: uv run ruff check src/ tests/
+
+    - name: Format check with ruff
+      run: uv run ruff format --check src/ tests/
+
+    - name: Type check with mypy
+      run: uv run mypy src/notebooklm_agent