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

python/sdk/README.md

@@ -0,0 +1,31 @@
+# MCP Interceptors Python SDK
+
+Python implementation of the Model Context Protocol (MCP) interceptor framework.
+
+## Installation
+
+```bash
+pip install mcp-ext-interceptors
+```
+
+## Usage
+
+```python
+from mcp_ext_interceptors import Interceptor
+
+# Example usage will be added as the implementation progresses
+```
+
+## Development
+
+```bash
+# Install in development mode
+pip install -e .
+
+# Run tests (when available)
+pytest
+```
+
+## License
+
+Apache License 2.0 - See LICENSE file in the root directory for details.