ShieldAuth - Modern Secure Authentication System with Advanced AI Assistant

A comprehensive, production-ready authentication application built with cutting-edge web technologies. ShieldAuth provides secure user authentication, role-based access control, a beautiful modern interface with advanced admin capabilities, and an integrated AI chatbot assistant with RAG (Retrieval Augmented Generation) capabilities for enhanced cybersecurity guidance.

🚀 Technology Stack

Frontend: SvelteKit with Svelte 5
Authentication: Auth.js with PostgreSQL Database Sessions (No JWT)
Styling: TailwindCSS with custom dark theme
Database: PostgreSQL with pgvector extension for vector embeddings
AI Integration: Google Gemini AI with streaming responses and RAG
Vector Database: pgvector for semantic search and embeddings
Embedding Service: Python FastAPI microservice with Gemini Embeddings API
Security: CSRF protection, bcrypt hashing, secure sessions
Deployment: Docker-ready with comprehensive configuration

✨ Core Features

🤖 ShieldBot AI Assistant with RAG

Intelligent Chat Interface

Real-time AI Chat - Interactive conversation with ShieldBot AI assistant
Word-by-Word Streaming - Natural typing effect with streaming responses
Context-Aware Responses - AI responses enhanced with retrieved document context
Citation Display - Shows which documents informed the AI's answer
File Upload Support - Upload documents (.txt, .doc, .docx, .pdf) for AI analysis
Multiple AI Models - Support for Gemini 2.5 Pro, 2.5 Flash, 1.5 Pro, and 1.5 Flash
Chat Management - Create, rename, delete, and organize chat conversations
Auto-Rename - Automatic chat naming based on first message topic
Responsive Design - Full-screen chat interface with collapsible sidebar

RAG (Retrieval Augmented Generation) Features

Document Ingestion - Upload and process documents for AI context
Semantic Search - Vector-based similarity search for relevant content
Context Retrieval - Automatic retrieval of relevant document snippets
Citation System - Track and display source documents with relevance scores
Chunking Strategy - Intelligent document chunking for optimal context
Embedding Generation - Automatic vector embeddings using Gemini API
Vector Storage - pgvector database for efficient similarity search
Relevance Gating - Only use document context when similarity is strong enough; otherwise answer from general knowledge

AI Features

Streaming Responses - Real-time word-by-word AI response streaming
Model Selection - Choose between different Gemini AI models
Chat History - Persistent chat conversations with timestamps
Security Guidance - Expert advice on password security, phishing protection, 2FA, and network security
Interactive Prompts - Pre-built conversation starters for common security topics
Markdown Rendering - Rich text formatting with syntax highlighting
Code Highlighting - Syntax highlighting for code blocks using Shiki
Citations in UI - Assistant messages show sources when document context is used

Advanced Message Management

Message Versioning - Complete forking system for message editing and branching
Edit Messages - Edit any user message to create conversation branches
Regenerate Responses - Generate new AI responses with streaming updates
Version Control - Track message versions with isActive flags and versionGroupId
Smart Context - AI maintains proper conversation context for versioned messages
First Message Protection - Prevents forking of initial messages with user-friendly popup
Editing UX - While saving an edit or regenerating, the chat disables send/regenerate and shows “Generating response…”

🔐 Authentication System

Multi-Method Authentication

Email/Password Registration - Secure account creation with email verification
Google OAuth Integration - One-click sign-in with Google accounts
GitHub OAuth Integration - Seamless GitHub authentication
Email Verification - 6-digit verification codes with spam folder alerts
Password Reset - Secure password recovery with email codes

Security Features

Database Sessions Only - No JWT tokens, secure server-side sessions
Bcrypt Password Hashing - Industry-standard password encryption
CSRF Protection - Built-in cross-site request forgery protection
Input Validation - Comprehensive server-side validation
Secure Headers - Security-focused HTTP headers
Profile Image Persistence - OAuth profile image/name synced on link/sign-in; DB image preferred to prevent flicker; avatars use referrerpolicy="no-referrer"

👑 Role-Based Access Control (RBAC)

Admin Dashboard

User Analytics - Real-time user statistics and metrics
System Overview - Complete system health and activity monitoring
Quick Actions - Fast access to common admin tasks
Modern UI - Beautiful gradient-based interface with dark theme

Advanced User Management

Search & Filter - Real-time search by name/email with role filtering
User Statistics - Dynamic user counts by role (Admin/Regular users)
Role Management - Promote/demote users between user and admin roles
Account Control - Delete user accounts with comprehensive data removal
Self-Protection - Admins cannot modify their own accounts
Activity Tracking - User registration and update timestamps

🎨 Modern User Interface

Dark Theme Design

Consistent Dark Mode - Beautiful black theme with blue accents throughout
Gradient Backgrounds - Modern gradient overlays and textures
Responsive Design - Perfect display on all devices and screen sizes
Professional Navigation - Role-based navigation with smooth transitions

Enhanced UX Features

Slide-up Animations - Smooth text animations on About and Contact pages
Interactive Elements - Hover effects, scale transforms, and smooth transitions
Form Validation - Real-time validation with user-friendly error messages
Loading States - Visual feedback during form submissions and API calls
Accessibility - ARIA labels, keyboard navigation, and screen reader support

📱 Page-Specific Features

Homepage

Hero Section - Engaging landing page with feature showcase
Feature Cards - Interactive cards highlighting system capabilities
ShieldBot Integration - AI chatbot card with purple theme and functional buttons
Call-to-Action - Beautiful gradient buttons for user engagement
Professional Footer - Complete site navigation and social links

ShieldBot Chat Interface

Full-Screen Chat - Immersive chat experience without navbar distractions
Collapsible Sidebar - Chat history and management with toggle functionality
Model Selection - Dropdown to choose AI model with real-time switching
Streaming Responses - Word-by-word AI response streaming for natural conversation
Chat Prompts - Pre-built conversation starters for security topics
Auto-Rename - Intelligent chat naming based on conversation topics
File Upload - Drag-and-drop file upload with validation
Citation Display - Show source documents with relevance scores
Doc-first Title - If the first message includes a file, the chat auto-renames to that document’s name

Enhanced Chat Management

Professional Rename Modal - Beautiful modal form for chat renaming with keyboard shortcuts
Smart Auto-Scroll - Automatic scrolling to bottom on new messages and page reload
Empty State UI - Beautiful interface when no conversations exist
Chat Deletion - Complete cleanup of messages and conversations with confirmation
Page Refresh Continuity - Resume last active chat after page reload
Hidden Scrollbars - Clean UI with custom scrollbar hiding throughout the interface
Keyboard Navigation - Enter/Escape key support for all modals and forms

Authentication Pages

Modern Login/Register - Purple-blue gradient themes with pattern backgrounds
Email Verification - 6-digit code input with individual digit fields
Password Management - Secure password change and reset workflows
Forgot Password - Email-based password recovery system
Alert Messages - "Check Spam Section" alerts for email verification

User Dashboard

Profile Management - Complete user profile with picture upload
Settings Panel - User preferences and account settings
Activity Overview - User activity and account information
Change Password - Secure password update with modern lock icon

Admin Interface

Dashboard Analytics - User statistics and system metrics
User Management - Advanced search, filtering, and user control
Role Administration - User role management and permissions
System Monitoring - Real-time system health and activity

🔧 Environment Configuration

Create a .env file in the root directory:

# Database Configuration (Required)
DATABASE_URL="postgresql://postgres:password@localhost:5433/authapp"

# Authentication Secret (Required)
AUTH_SECRET="your-super-secret-auth-key-here"

# AI Configuration (Required for ShieldBot)
GOOGLE_AI_API_KEY="your-google-ai-api-key"

# Embedding Service Configuration (Required for RAG)
EMBEDDING_API_URL="http://localhost:8000"
# Embedding target dimension (must match DB vector column; defaults to 3072)
EMBEDDING_TARGET_DIM="3072"

# OAuth Configuration (Optional)
GOOGLE_CLIENT_ID="your-google-client-id"
GOOGLE_CLIENT_SECRET="your-google-client-secret"
GITHUB_CLIENT_ID="your-github-client-id"
GITHUB_CLIENT_SECRET="your-github-client-secret"

# Environment
NODE_ENV="development"

Important Notes:

Uses PostgreSQL with pgvector - no SQLite fallback
Custom port 5433 to avoid conflicts
Generate secure AUTH_SECRET: openssl rand -base64 32
Google AI API Key required for ShieldBot functionality
Embedding API URL required for RAG functionality
OAuth credentials are optional

🏗️ Project Structure

src/
├── lib/
│   ├── components/          # Reusable UI components
│   │   ├── Button.svelte
│   │   ├── Card.svelte
│   │   ├── Input.svelte
│   │   ├── Notification.svelte
│   │   ├── EnhancedMessageRenderer.svelte
│   │   └── MarkdownRenderer.svelte    # Markdown with syntax highlighting
│   ├── server/              # Server-side utilities
│   │   ├── auth.ts          # Auth.js configuration
│   │   ├── ai.ts            # AI service integration
│   │   ├── db/              # Database schema and connection
│   │   │   ├── schema.ts    # Main database schema
│   │   │   └── rag.schema.ts # RAG-specific tables
│   │   ├── email.ts         # Email service
│   │   └── security.ts      # Security utilities
│   ├── services/            # Client-side services
│   │   ├── clientChatService.ts  # AI chat service
│   │   └── databaseChatService.ts # Database chat operations
│   └── stores/              # Svelte stores
│       └── chatStore.ts     # Chat state management
├── routes/                  # Application routes
│   ├── api/                 # API endpoints
│   │   ├── auth/            # Authentication endpoints
│   │   ├── chat/            # AI chat streaming endpoints
│   │   └── rag/             # RAG endpoints
│   │       ├── ingest/      # Document ingestion
│   │       └── retrieve/    # Context retrieval
│   ├── admin/               # Admin-only pages
│   ├── auth/                # Authentication pages
│   ├── chatbot/             # ShieldBot AI chat interface
│   └── (pages)/             # Public and protected pages
└── static/                  # Static assets

embedding-service/           # Python microservice
├── app.py                   # FastAPI embedding service
├── Dockerfile              # Container configuration
└── requirements.txt        # Python dependencies

🚀 Quick Start

1. Clone and Install

git clone https://github.com/Vanar-AI-Excellence-Program/Assignment-3-Ahmed-Asghar-and-Aatiqa-Hussain
cd Assignment-3-Ahmed-Asghar-and-Aatiqa-Hussain
npm install

2. Database Setup

# Start PostgreSQL with pgvector (custom port 5433)
docker-compose up -d

# Push database schema
npm run db:push

3. Environment Configuration

Create a .env file in the root directory with the following variables:

# Database Configuration
DATABASE_URL="postgresql://postgres:password@localhost:5433/Authapp"

# Authentication Configuration
AUTH_SECRET="your-auth-secret-here-generate-a-long-random-string"
AUTH_TRUST_HOST=true

# OAuth Configuration (Optional)
GOOGLE_CLIENT_ID="your-google-client-id"
GOOGLE_CLIENT_SECRET="your-google-client-secret"
GITHUB_CLIENT_ID="your-github-client-id"
GITHUB_CLIENT_SECRET="your-github-client-secret"

# AI Configuration (Required for ShieldBot)
GOOGLE_AI_API_KEY="your-google-ai-api-key"

# Embedding Service Configuration (Required for RAG)
EMBEDDING_API_URL="http://localhost:8000"
# Optional: override embedding dimension exposed by the Python service
EMBEDDING_TARGET_DIM="3072"

# Email Configuration (Optional - for email verification and password reset)
SENDGRID_API_KEY="your-sendgrid-api-key"
FROM_EMAIL="noreply@yourdomain.com"

# Application Configuration
NODE_ENV="development"

Important: Both GOOGLE_AI_API_KEY and EMBEDDING_API_URL are required for full ShieldBot functionality.

4. Start Development

# Start the embedding service
docker-compose up embedding-service -d

# Verify embedding service
curl http://localhost:8000/health

# Start the main application
npm run dev

Visit http://localhost:5173 to see your application!

🤖 ShieldBot AI Features

Getting Started with ShieldBot

Navigate to Chatbot - Click "Start Chat" on the homepage or visit /chatbot
Choose AI Model - Select from Gemini 2.5 Pro, 2.5 Flash, 1.5 Pro, or 1.5 Flash
Start Conversation - Use pre-built prompts or ask your own security questions
Upload Documents - Upload files for AI to analyze and reference
Streaming Responses - Watch AI responses appear word-by-word in real-time
View Citations - See which documents informed the AI's answer
Out-of-Doc Questions - If retrieval is not relevant enough, ShieldBot answers from its general knowledge

RAG Capabilities

Document Analysis - Upload and analyze security documents, policies, and guides
Context-Aware Responses - AI responses enhanced with relevant document content
Citation Tracking - See exactly which documents and sections informed each answer
Semantic Search - Find relevant content using vector similarity
Multi-Format Support - Support for .txt, .doc, .docx, and .pdf files
Configurable Relevance - Document context is only attached when similarity passes an internal threshold (default ~0.62 cosine-like). You can raise/lower this threshold in src/lib/server/ai.ts if needed.

AI Capabilities

Password Security - Best practices for strong passwords
Phishing Protection - How to identify and avoid phishing scams
Two-Factor Authentication - Benefits and setup guidance
Network Security - Securing home Wi-Fi and devices
General Cybersecurity - Comprehensive security advice
Document-Specific Guidance - AI responses based on uploaded documents

Chat Management

Auto-Rename - Chats automatically named based on first message
Manual Rename - Custom chat titles for organization
Chat History - Persistent conversation storage
Delete Chats - Remove unwanted conversations
New Chat - Start fresh conversations anytime
File Attachments - Upload and reference documents in conversations

👑 Admin Features

Getting Admin Access

npm run promote-admin your-email@example.com

Admin Capabilities

Dashboard: /admin - System analytics and overview
User Management: /admin/users - Advanced user administration
Search & Filter: Real-time user search by name/email
Role Management: Promote/demote users between roles
Account Control: Delete user accounts with full data removal
Statistics: Dynamic user counts and activity metrics

🔗 OAuth Integration

Supported Providers

Google OAuth - Sign in with Google account
GitHub OAuth - Sign in with GitHub account
Email/Password - Traditional authentication

OAuth Features

Seamless Integration - One-click social authentication
Account Linking - OAuth accounts linked to email accounts
Profile Sync - Automatic name and picture sync from providers
Flexible Authentication - Multiple authentication methods per user

📱 Application Routes

Public Routes

/ - Homepage with feature showcase and ShieldBot card
/about - About page with slide-up animations
/contact - Contact page with modern UI
/register - User registration with email verification
/login - User login with OAuth options

AI Chat Routes

/chatbot - ShieldBot AI chat interface with streaming responses and RAG

Authentication Routes

/verify-code - Email verification with 6-digit codes
/forgot-password - Password recovery request
/reset-password-code - Password reset code entry
/reset-password - New password creation
/change-password-code - Password change verification
/change-password - Password update

Protected Routes

/dashboard - User dashboard with profile overview
/profile - Profile management with picture upload
/change-password - Secure password change

Admin Routes

/admin - Admin dashboard with analytics
/admin/users - User management with search/filter

API Endpoints

/api/auth/* - Authentication endpoints
/api/profile/* - Profile management
/api/admin/users/* - Admin user management
/api/chat/stream - AI chat streaming endpoint
/api/rag/ingest - Document ingestion endpoint
/api/rag/retrieve - Context retrieval endpoint

Chat Management API

/api/chat/conversations - Create and list conversations
/api/chat/conversations/[id]/delete - Delete conversation with message cleanup
/api/chat/conversations/[id]/rename - Rename conversation
/api/chat/messages/[id]/edit - Edit message with versioning
/api/chat/messages/[id]/regenerate - Regenerate AI response with streaming
/api/chat/messages/[id]/versions - Get message versions

🛠️ Development Scripts

Development

npm run dev          # Start development server
npm run build        # Build for production
npm run preview      # Preview production build
npm run check        # Type checking and linting

Database Management

npm run db:up        # Start PostgreSQL database
npm run db:down      # Stop PostgreSQL database
npm run db:push      # Push database schema changes
npm run db:studio    # Open Drizzle Studio
npm run seed         # Seed database with sample data

Admin Tools

npm run promote-admin <email>  # Promote user to admin role

Docker Services

docker-compose up -d                    # Start all services
docker-compose up embedding-service -d  # Start only embedding service
docker-compose down                     # Stop all services

🎯 Key Features Breakdown

RAG System Flow

Document Upload → File validation → Text extraction → Chunking
Embedding Generation → Python service → Gemini API → Vector storage
Context Retrieval → User query → Vector similarity → Relevant chunks
AI Enhancement → Context + query → Enhanced AI response → Citations

AI Chat Flow

Model Selection → Choose AI model → Start conversation
Streaming Response → Word-by-word streaming → Real-time display
Context Integration → RAG context → Enhanced responses → Citations
Chat Management → Auto-rename → Manual organization
Security Guidance → Expert advice → Interactive learning

Message Versioning Flow

Edit Message → Click edit button → Modify content → Save changes
Version Creation → New message version created → Previous version deactivated
AI Regeneration → Regenerate AI response → Streaming update → Context preserved
Version Navigation → View message history → Switch between versions
Context Maintenance → AI maintains conversation context across versions

Authentication Flow

Registration → Email verification → Account activation
Login → Database session creation → Protected access
Password Reset → Email code → New password creation
OAuth Login → Provider authentication → Account linking

Admin Workflow

User Search → Real-time filtering → Role management
Account Control → User deletion → Complete data removal
Analytics → User statistics → System monitoring
Security → Self-protection → Audit trail

UI/UX Features

Dark Theme → Consistent black theme with blue accents
Animations → Slide-up text animations and smooth transitions
Responsive → Perfect display on all devices
Accessibility → ARIA labels and keyboard navigation
Streaming → Real-time AI response streaming
Markdown → Rich text formatting with syntax highlighting

Enhanced Chat Experience

Auto-Scroll → Automatic scrolling to bottom on new messages
Hidden Scrollbars → Clean UI with custom scrollbar hiding
Keyboard Shortcuts → Enter/Escape key support for all modals
Professional Modals → Beautiful modal forms instead of browser prompts
Empty States → Beautiful UI when no conversations exist
Page Continuity → Resume last active chat after page reload
File Upload → Drag-and-drop file upload with validation
Citation Display → Source documents with relevance scores

🔒 Security Implementation

Session Management

Database Sessions - Server-side session storage
30-day Expiration - Automatic session cleanup
Secure Cookies - HttpOnly, Secure, SameSite attributes
CSRF Protection - Built-in cross-site request forgery protection

Message Versioning Security

Version Control - Secure message versioning with versionGroupId and isActive flags
Context Integrity - AI maintains proper conversation context for versioned messages
Data Consistency - Proper cleanup of related messages when conversations are deleted
First Message Protection - Prevents forking of initial messages to maintain conversation integrity

Password Security

Bcrypt Hashing - Industry-standard password encryption
Salt Rounds - Configurable encryption strength
Password Validation - Strong password requirements
Secure Reset - Email-based password recovery

Input Validation

Server-side Validation - All inputs validated on server
Type Safety - TypeScript implementation throughout
SQL Injection Protection - Drizzle ORM parameterized queries
XSS Protection - Input sanitization and output encoding

AI Security

API Key Protection - Secure server-side AI API key handling
Input Sanitization - All user inputs sanitized before AI processing
Rate Limiting - Protection against AI API abuse
Error Handling - Graceful AI service error management

RAG Security

File Validation - Strict file type and size validation
Content Sanitization - All uploaded content sanitized before processing
Vector Security - Secure embedding generation and storage
Access Control - User-specific document access and retrieval
Thresholding - Irrelevant context is ignored to avoid data leakage from unrelated documents

🧪 Troubleshooting

Embeddings not saved:
- Ensure the embedding service is running: curl http://localhost:8000/health should return status ok and target_dim: 3072.
- Confirm your DB has pgvector and the embeddings column dimensions match 3072.
- Check server logs for Saved embedding for chunk messages.
Always citing docs for out-of-scope questions:
- The system now gates context by similarity. If it still feels too eager, increase the threshold in src/lib/server/ai.ts.
OAuth avatar missing or late:
- We persist the provider image on link/sign-in and prefer the DB image in session. Clear cache and refresh.
Edit/regenerate buttons clickable during generation:
- The UI disables these while generating and shows a status label. If you don’t see this, rebuild the app.

🚀 Deployment

Production Checklist

✅ Set NODE_ENV=production
✅ Configure production database URL
✅ Set secure AUTH_SECRET
✅ Configure GOOGLE_AI_API_KEY for ShieldBot
✅ Configure EMBEDDING_API_URL for RAG
✅ Enable SSL for database connections
✅ Configure reverse proxy
✅ Set up monitoring and logging

Docker Deployment

# Build and run with Docker Compose
docker-compose up -d

# Check service status
docker-compose ps

# View logs
docker-compose logs -f

📊 Performance Optimizations

Frontend

Code Splitting - Automatic bundle optimization
Component Library - Reusable, optimized components
TailwindCSS Purging - Optimized CSS for production
Image Optimization - Compressed and optimized assets
Streaming Optimization - Efficient AI response streaming
Markdown Rendering - Optimized syntax highlighting

Backend

Connection Pooling - Efficient database connections
Query Optimization - Optimized database queries
Caching - Strategic caching implementation
Error Handling - Graceful error management
AI Response Caching - Optimized AI service calls
Vector Indexing - Optimized vector similarity search

RAG System

Chunking Strategy - Optimal document chunking for context
Vector Indexing - Efficient similarity search with pgvector
Embedding Caching - Cached embeddings for performance
Context Filtering - Smart context selection and ranking

Message Versioning System

Tree Structure - Messages organized in tree structure with parentId relationships
Version Groups - Messages grouped by versionGroupId for easy version tracking
Active Flags - isActive flag to identify current version of each message
Version Numbers - Sequential versionNumber for version ordering
Context Preservation - AI maintains conversation context across message versions
Data Integrity - Proper cleanup of related messages when conversations are deleted

🤝 Contributing

Fork the repository
Create a feature branch (git checkout -b feature/amazing-feature)
Commit your changes (git commit -m 'Add amazing feature')
Push to the branch (git push origin feature/amazing-feature)
Open a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

SvelteKit - The web framework
Auth.js - Authentication for the web
TailwindCSS - Utility-first CSS framework
Drizzle ORM - TypeScript ORM
PostgreSQL - Advanced open source database
pgvector - Vector similarity search
Google Gemini AI - Advanced AI capabilities
Shiki - Syntax highlighting
FastAPI - Python web framework

ShieldAuth - Built with ❤️ using modern web technologies for secure, scalable authentication with intelligent AI assistance and advanced RAG capabilities.

🔮 Recent Updates

v4.0 - Complete RAG Integration 🎉

🧠 Advanced RAG System

✅ Document Ingestion - Upload and process documents for AI context
✅ Vector Embeddings - Automatic embedding generation using Gemini API
✅ Semantic Search - Vector-based similarity search with pgvector
✅ Context Retrieval - Automatic retrieval of relevant document snippets
✅ Citation System - Track and display source documents with relevance scores
✅ Python Microservice - Containerized embedding service with FastAPI

💬 Enhanced AI Chat Experience

✅ Context-Aware Responses - AI responses enhanced with retrieved document context
✅ File Upload Support - Upload .txt, .doc, .docx, .pdf files for analysis
✅ Citation Display - Show which documents informed the AI's answer
✅ Markdown Rendering - Rich text formatting with syntax highlighting
✅ Code Highlighting - Syntax highlighting for code blocks using Shiki
✅ Streaming Integration - Real-time streaming with context integration

🔧 Technical Improvements

✅ pgvector Integration - PostgreSQL with vector similarity search
✅ Embedding Service - Python FastAPI microservice for embeddings
✅ Database Schema - RAG tables for documents, chunks, and embeddings
✅ API Endpoints - Document ingestion and context retrieval endpoints
✅ Error Handling - Comprehensive error handling for RAG operations
✅ Performance - Optimized vector search and context retrieval

v3.0 - Complete Forking Implementation 🎉

🤖 Enhanced AI Chat Experience

✅ Message Versioning - Complete message forking and versioning system
✅ Edit & Regenerate - Edit any message or regenerate AI responses
✅ Smart Context Handling - AI maintains proper conversation context for versioned messages
✅ Streaming Regeneration - Real-time streaming for regenerated responses
✅ First Message Protection - Prevents forking of first messages with user-friendly popup

💬 Advanced Chat Management

✅ Professional Rename Modal - Beautiful modal form instead of browser prompts
✅ Smart Auto-Rename - Automatic chat naming based on conversation topics
✅ Chat Deletion - Complete cleanup of messages and conversations
✅ Empty State Handling - Beautiful UI when no conversations exist
✅ Page Refresh Continuity - Resume last active chat after page reload

🎨 Enhanced User Interface

✅ Auto-Scroll Functionality - Smooth scrolling to bottom on new messages
✅ Hidden Scrollbars - Clean UI with custom scrollbar hiding
✅ Keyboard Shortcuts - Enter/Escape key support for all modals
✅ Responsive Design - Perfect display on all devices
✅ Dark Theme Consistency - Unified dark theme throughout