Auto-generate tests for a file or function.

## Features
- **Framework Detection**: Automatically detects pytest, unittest, jest, go test, etc.
- **Comprehensive Coverage**: Happy path, edge cases, error handling
- **Style Matching**: Follows patterns from existing tests in the project
- **Smart Mocking**: Identifies external dependencies to mock

## Parameters
- `file` (required): Path to the source file
- `function`: Optional function/class name to focus on
- `framework`: Override auto-detected framework
- `output_file`: Path to write generated tests

## Examples

Generate tests for a Python file:
```json
{"file": "src/auth.py"}
```

Generate tests for a specific function:
```json
{"file": "src/utils.py", "function": "parse_config"}
```

Generate and save tests:
```json
{"file": "src/api.py", "output_file": "tests/test_api.py"}
```

Force a specific framework:
```json
{"file": "src/handler.ts", "framework": "jest"}
```
