Add llms-full.txt file for enhanced AI coding tool support (#570)

## Summary

Fixes #569

• Add new comprehensive documentation file `llms-full.txt` covering
complete LangChain AWS integration guide
• Provide production-ready examples and best practices for all AWS
services (Bedrock, SageMaker, Kendra, Neptune)
• Include advanced use cases, security patterns, and deployment guidance
for enterprise users

## Changes Made

### New Documentation File Added
- **`llms-full.txt`** - Complete guide for LangChain AWS integrations
following modern documentation standards

### Key Documentation Sections
- **Prerequisites and Setup** - AWS credential configuration and package
installation
- **TLDR Quick Start** - Immediate working example for ChatBedrock
- **Core Components** - Detailed coverage of all major AWS integrations:
  - ChatBedrock and ChatBedrockConverse for foundation models
  - BedrockEmbeddings for vector representations
  - AmazonKendraRetriever and AmazonKnowledgeBasesRetriever for search
  - SagemakerEndpoint for custom model deployments
  - Neptune graph database integrations

### Advanced Implementation Patterns
- **RAG Pipeline** - Complete retrieval-augmented generation
implementation
- **Multi-Modal AI** - Image analysis with Claude 3 vision models  
- **Function Calling** - Agent patterns with tool integration
- **Semantic Search** - Vector storage and similarity search
- **Batch Processing** - Efficient handling of large datasets

### Production-Ready Features
- **Error Handling** - Robust retry logic with exponential backoff
- **Cost Optimization** - Model routing and usage monitoring
- **Security** - Input sanitization and sensitive data protection
- **Testing** - Unit and integration test patterns
- **Monitoring** - Performance tracking and logging
- **Deployment** - Docker configuration and environment setup

### Developer Experience Improvements
- Complete working code examples for every component
- Step-by-step implementation guides
- Common troubleshooting scenarios and solutions
- Production deployment checklist
- Links to additional resources and community support

Author: ravediamond