Fix v0 server code extraction and add enhanced features

[vanman2024]

Problem

The v0 MCP server has several issues that need to be addressed:

1. Code Extraction Issues: The server saves entire AI responses including markdown artifacts instead of just the code
2. File Path Handling: Multi-file responses don't create proper directory structures
3. Missing Features: No ability to update files in-place or create complete features
4. Poor Error Handling: No rate limiting, validation, or retry logic

Solution

Implement comprehensive fixes and enhancements:

Code Extraction Fixes

• Improve regex patterns to properly extract code from markdown blocks
• Handle file markers like ```tsx file="path/to/file.ext" `
• Remove language identifiers and closing backticks

Enhanced Features

• Add write_to_file parameter for direct file creation
• Implement v0_update_file function for in-place updates
• Add v0_create_feature for complete feature generation
• Enhance improve_component with file writing capability

Error Handling & Validation

• Add RateLimiter class (10 calls/minute default)
• Input validation (empty prompts, max 10000 chars)
• Tech stack validation with warnings
• Retry logic (3 attempts, 5-second delays)
• Security validation for file paths
• 60-second timeout for API calls

Testing

• Multi-file generation with proper paths
• Code extraction without artifacts
• Rate limiting under load
• File update functionality
• Feature generation with multiple components

Branch

feat/v0-server-major-improvements