Implement smoke test for clients and servers (#76)

This commit adds `tests/smoke-test.sh`, which performs a smoke test of
all clients and servers. The smoke test tests that the clients and
servers run and that list tools is called.

This commit also adds a GitHub Actions workflow to run the smoke test on
all pull requests and pushes to main.

For practicality, this commit modifies the TypeScript and Python clients
to lazily initialize the Anthropic client, thus allowing tests to skip
setting an API key. This change also provides a friendly error when
users forget to set an API key.

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

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Alex Akimov <alexeyakimov@gmail.com>

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: Smoke Tests
+
+on:
+  pull_request:
+    branches: [main]
+  push:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "18"
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install uv
+        run: |
+          curl -LsSf https://astral.sh/uv/install.sh | sh
+          echo "$HOME/.cargo/bin" >> $GITHUB_PATH
+
+      - name: Set up Rust
+        uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: stable
+
+      - name: Run smoke tests
+        run: ./tests/smoke-test.sh