feat: Add GitHub infrastructure, CI/CD pipelines, and examples

- Add GitHub issue templates (bug, feature, docs)
- Add pull request template with closed-source checklist
- Add CODEOWNERS for code review assignment
- Add CI/CD workflows (ci, lint, security, docs, release)
  - pytest + coverage with Python 3.10/3.11 matrix
  - Ruff + MyPy code quality checks
  - Bandit + safety security scanning
  - Sphinx docs + GitHub Pages deployment
  - Automated PyPI releases on tag push
- Add 6 comprehensive examples + Jupyter quickstart
  - 01_factor_discovery.py (LLM factor generation)
  - 02_factor_evolution.py (factor optimization)
  - 03_strategy_generation.py (IC-weighted combination)
  - 04_backtest_simple.py (strategy backtesting)
  - 05_model_training.py (XGBoost/LSTM training)
  - 06_rl_trading_agent.py (PPO/DQN/A2C agents)
  - notebooks/quickstart.ipynb (interactive tutorial)
- Restructure .gitignore with explicit closed-source sections
- Add CI/coverage/license badges to README
- Complete CLI docstrings for all 9 commands
- Add data_config.yaml for quant loop configuration

.github/workflows/docs.yml

@@ -0,0 +1,83 @@
+name: Documentation
+
+on:
+  push:
+    branches: [ main ]
+    paths:
+      - 'docs/**'
+      - 'README.md'
+      - '**/*.rst'
+      - '.github/workflows/docs.yml'
+  pull_request:
+    branches: [ main ]
+    paths:
+      - 'docs/**'
+      - 'README.md'
+      - '**/*.rst'
+
+jobs:
+  docs:
+    name: Build Documentation
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    - name: Set up Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: "3.10"
+
+    - name: Cache pip dependencies
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-docs-${{ hashFiles('**/pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-docs-
+
+    - name: Install docs dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -e ".[docs]"
+
+    - name: Build Sphinx documentation
+      run: |
+        cd docs
+        make clean
+        make html SPHINXOPTS="-W --keep-going" || {
+          echo "::error::Sphinx build failed with warnings"
+          exit 1
+        }
+
+    - name: Check for broken links
+      run: |
+        cd docs
+        make linkcheck || {
+          echo "::warning::Some links are broken (non-blocking)"
+          exit 0
+        }
+
+    - name: Upload docs artifact
+      if: github.ref == 'refs/heads/main'
+      uses: actions/upload-pages-artifact@v3
+      with:
+        path: docs/_build/html
+
+  deploy:
+    name: Deploy to GitHub Pages
+    needs: docs
+    if: github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+
+    steps:
+    - name: Deploy to GitHub Pages
+      id: deployment
+      uses: actions/deploy-pages@v4