Initial project structure for MCP interceptors (#3)

Establishes a multi-language monorepo structure for MCP interceptors
with Python and TypeScript SDKs alongside the existing Go
implementation. Implements an efficient CI/CD system that only tests
what changes.


#### 🏗️ SDK Scaffolding
- **Python SDK** (`python/sdk/`): Modern Python package using
`pyproject.toml`, aligned with official MCP Python SDK patterns
- **TypeScript SDK** (`typescript/sdk/`): ESM-based package structure,
compatible with official MCP TypeScript SDK
- **Monorepo structure**: Consistent `{language}/sdk/` pattern across
all implementations
  
 #### 🚀 CI/CD Pipeline
- **Path-based workflow triggering**: Only runs CI for languages that
actually changed
    - Change Python → only Python CI runs
    - Change multiple languages → only those CIs run
- **Status check workflow**: Single required check that dynamically
validates based on changes
- **Comment triggers**: Maintainers can run all checks with `/test all`
PR comment

.github/workflows/python.yml

@@ -0,0 +1,67 @@
+name: Python CI
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'python/**'
+      - '.github/workflows/python.yml'
+  pull_request:
+    paths:
+      - 'python/**'
+      - '.github/workflows/python.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  python-lint:
+    name: "Linting"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      - name: Install dependencies
+        run: |
+          cd python/sdk
+          pip install -e .
+          pip install ruff mypy
+      - name: Run Ruff formatter check
+        run: |
+          cd python/sdk
+          ruff format --check .
+      - name: Run Ruff linter
+        run: |
+          cd python/sdk
+          ruff check .
+      - name: Run mypy
+        run: |
+          cd python/sdk
+          mypy src/mcp_ext_interceptors --ignore-missing-imports
+
+  python-test:
+    name: "Unit Tests"
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.10", "3.11", "3.12"]
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          cd python/sdk
+          pip install -e .
+          pip install pytest pytest-cov
+      - name: Run tests
+        run: |
+          cd python/sdk
+          pytest -v --cov=src/mcp_ext_interceptors