Add comprehensive database integration, authentication, and admin dashboard

This commit introduces major enhancements to Talk2Me:

## Database Integration
- PostgreSQL support with SQLAlchemy ORM
- Redis integration for caching and real-time analytics
- Automated database initialization scripts
- Migration support infrastructure

## User Authentication System
- JWT-based API authentication
- Session-based web authentication
- API key authentication for programmatic access
- User roles and permissions (admin/user)
- Login history and session tracking
- Rate limiting per user with customizable limits

## Admin Dashboard
- Real-time analytics and monitoring
- User management interface (create, edit, delete users)
- System health monitoring
- Request/error tracking
- Language pair usage statistics
- Performance metrics visualization

## Key Features
- Dual authentication support (token + user accounts)
- Graceful fallback for missing services
- Non-blocking analytics middleware
- Comprehensive error handling
- Session management with security features

## Bug Fixes
- Fixed rate limiting bypass for admin routes
- Added missing email validation method
- Improved error handling for missing database tables
- Fixed session-based authentication for API endpoints

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

run_dev_server.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+# Run Talk2Me development server locally
+
+echo "Starting Talk2Me development server..."
+echo "=================================="
+echo "Admin Dashboard: http://localhost:5005/admin"
+echo "  Token: 4CFvwzmeDWhecfuOHYz7Hyb8nQQ="
+echo ""
+echo "User Login: http://localhost:5005/login"
+echo "  Username: admin"
+echo "  Password: talk2me123"
+echo ""
+echo "API Authentication:"
+echo "  API Key: 6sy2_m8e89FeC2RmUo0CcgufM9b_0OoIwIa8LSEbNhI"
+echo "=================================="
+echo ""
+
+# Kill any existing process on port 5005
+lsof -ti:5005 | xargs kill -9 2>/dev/null
+
+# Set environment variables
+export FLASK_ENV=development
+export FLASK_DEBUG=1
+
+# Run with gunicorn for a more production-like environment
+gunicorn --bind 0.0.0.0:5005 \
+         --workers 1 \
+         --threads 2 \
+         --timeout 120 \
+         --reload \
+         --log-level debug \
+         wsgi:application