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/lint.yml

@@ -0,0 +1,81 @@
+name: Code Quality
+
+on:
+  push:
+    branches: [ main, develop ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  lint:
+    name: Lint & Format
+    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: ${{ runner.os }}-pip-lint-${{ hashFiles('**/pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-lint-
+
+    - name: Install lint dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install ruff mypy
+
+    - name: Run Ruff (linter)
+      run: |
+        echo "=== Running Ruff Linter ==="
+        ruff check . --statistics || {
+          echo "::error::Ruff linter found issues. Run: ruff check . --fix"
+          exit 1
+        }
+
+    - name: Run Ruff (formatter)
+      run: |
+        echo "=== Running Ruff Formatter ==="
+        ruff format --check . || {
+          echo "::error::Ruff formatter found issues. Run: ruff format ."
+          exit 1
+        }
+
+    - name: Run MyPy (type checker)
+      run: |
+        echo "=== Running MyPy Type Checker ==="
+        mypy rdagent/ \
+          --ignore-missing-imports \
+          --no-strict-optional \
+          --follow-imports=skip \
+          --warn-return-any || {
+          echo "::warning::MyPy found type issues (non-blocking)"
+          # Non-blocking: MyPy warnings don't fail the build
+          exit 0
+        }
+
+    - name: Check for trailing whitespace
+      run: |
+        echo "=== Checking for trailing whitespace ==="
+        if grep -rIn '[[:space:]]$' --include='*.py' --include='*.md' --include='*.rst' . | grep -v '.git'; then
+          echo "::error::Found trailing whitespace. Please remove it."
+          exit 1
+        fi
+        echo "✓ No trailing whitespace found"
+
+    - name: Check for merge conflicts
+      run: |
+        echo "=== Checking for merge conflict markers ==="
+        if grep -rn '<<<<<<< HEAD\|=======\|>>>>>>>' --include='*.py' --include='*.md' . | grep -v '.git'; then
+          echo "::error::Found merge conflict markers. Please resolve them."
+          exit 1
+        fi
+        echo "✓ No merge conflict markers found"