Add CI workflow for Claude Code SDK e2e testing (#154)

## Summary
- Added GitHub Actions workflow to test SDK integration with Claude Code
CLI
- Tests run on PR open/synchronize events across Python 3.10-3.13

## Test plan
- [x] Workflow triggers on PR events
- [x] Installs Claude Code CLI via official script
- [x] Runs quickstart example
- [x] Runs streaming_mode example

🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/test-e2e.yml

@@ -0,0 +1,43 @@
+name: Claude Code E2E Test
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  integration-test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Claude Code
+        run: |
+          curl -fsSL https://claude.ai/install.sh | bash
+          echo "$HOME/.local/bin" >> $GITHUB_PATH
+
+      - name: Verify Claude Code installation
+        run: claude -v
+
+      - name: Install Python dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e .
+
+      - name: Run quickstart example
+        run: python examples/quick_start.py
+        env:
+          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
+
+      - name: Run streaming mode examples
+        run: timeout 120 python examples/streaming_mode.py all
+        env:
+          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}