feat(NGUI-330): Split ngui-e2e architecture and update deployment strategy

[Hrithik-Gavankar]

What's Changed

Split Architecture Implementation:

• Restructured ngui-e2e into separate server/ and client/ directories
• Moved FastAPI backend to server/main.py
• Organized React frontend under client/ folder

Deployment Strategy Update:

• Rewrote deployment plan for Lightrail (backend) + frontend platform alternatives
• Merged executive summary into single comprehensive deployment document
• Updated for models.corp LLaMA integration

Documentation Improvements:

• Moved README to root ngui-e2e/ level covering both components
• Updated setup instructions for split architecture
• Fixed paths and model references (llama3.2:3b)

Error Handling & Robustness:

• Added comprehensive error handling for dynamic UI components
• Implemented React Error Boundary for graceful failure handling
• Enhanced server-side validation for agent responses
• Added client-side component validation with fallback UI
• Improved error messages and debugging capabilities

Development Workflow Improvements:

• Fixed React version compatibility issues (peerDependencies)
• Updated Vite configuration for proper React externalization
• Enhanced TypeScript compilation with proper type handling
• Added environment variable management (.env.sample files)
• Cleaned up unnecessary development files

Why This Change?

• Better Deployment Flexibility: Enables independent server/client deployment
• Clearer Project Structure: Logical separation of concerns
• Production Ready: Prepared for Lightrail + Vercel/SSR deployment
• Improved DX: Easier navigation and setup for contributors
• Enhanced Reliability: Robust error handling prevents UI breakage
• Future-Proof: React version compatibility for 18+ versions

Testing

• Backend starts successfully from server/ directory
• Frontend runs from client/ directory
• Updated README instructions work end-to-end
• Deployment plan reflects current architecture
• Error handling works for invalid/missing components
• TypeScript compilation passes without errors
• React Error Boundary catches rendering failures
• Server validates agent responses properly

📋 Breaking Changes

⚠️ Path Changes: Update any scripts/docs referencing old main.py location
⚠️ Import Changes: Updated React imports to use type-only imports where appropriate

[velias]

@lkrzyzanek can you check this please, why it was missing?