🔄 Add Template Migration to CLI

Summary

This PR introduces a new migrate command to the E2B CLI that helps users transition from the legacy Dockerfile + TOML configuration format to the new Template SDK format. The migration tool automatically converts existing e2b.Dockerfile and e2b.toml configurations into SDK-compatible template files using Handlebars templates.

What's Changed

✨ New Features

• Template Migration Command: Added e2b template migrate command for converting legacy configurations to SDK format
• Multi-Language Support: Supports migration to TypeScript, Python (sync), and Python (async) formats
• Interactive Language Selection: CLI prompts for target language when not specified
• Multi-stage Dockerfile Support: Added fallback handling for complex multi-stage Dockerfiles

🔧 Technical Improvements

• Enhanced ENV Handling: Improved parsing of multiple environment variables from single ENV instructions
• File Name Conflict Resolution: Automatic unique filename generation to prevent overwriting existing files
• Comprehensive Template Generation: Creates both development and production build files

📁 New Template Files

• typescript-template.hbs - TypeScript template generation
• typescript-build.hbs - TypeScript build script template
• python-template.hbs - Python template generation (supports both sync/async)
• python-build-async.hbs - Python async build script template
• python-build-sync.hbs - Python sync build script template

Usage

# Migrate with interactive language selection
e2b template migrate

# Migrate to specific language
e2b template migrate --language typescript
e2b template migrate --language python-sync
e2b template migrate --language python-async

# Custom paths
e2b template migrate --dockerfile custom.dockerfile --config custom.toml

Generated Output

The migration command generates three files per target:

• template.{ts|py} - Template definition using SDK
• build{.|_}dev.{ts|py} - Development build script
• build{.|_}prod.{ts|py} - Production build script

Migration Process

1. Parse Configuration: Reads e2b.toml for template settings
2. Dockerfile Analysis: Uses E2B SDK to parse Dockerfile instructions
3. Transformation: Converts Docker instructions to SDK method calls
4. Code Generation: Uses Handlebars templates to generate target language files
5. File Creation: Writes template and build files with conflict resolution

Error Handling

• Graceful Dockerfile Parsing: Falls back to custom image reference for unparseable Dockerfiles
• Clear User Guidance: Provides manual build instructions when automatic conversion fails
• Validation: Ensures required configuration files exist before migration