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>

init_auth_db.py

@@ -0,0 +1,149 @@
+#!/usr/bin/env python3
+"""Initialize authentication database and create default admin user"""
+
+import os
+import sys
+import getpass
+from flask import Flask
+from flask_sqlalchemy import SQLAlchemy
+from dotenv import load_dotenv
+
+# Load environment variables
+load_dotenv()
+
+# Add parent directory to path
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+
+from config import init_app as init_config
+from database import db, init_db
+from auth_models import User, bcrypt
+from auth import create_user
+
+def create_admin_user():
+    """Create the default admin user"""
+    # Skip if running non-interactively
+    if not sys.stdin.isatty():
+        print("Running non-interactively, skipping interactive admin creation.")
+        return True
+        
+    print("\n=== Talk2Me Admin User Setup ===\n")
+    
+    # Get admin credentials
+    while True:
+        email = input("Admin email: ").strip()
+        if '@' in email and '.' in email:
+            break
+        print("Please enter a valid email address.")
+    
+    while True:
+        username = input("Admin username: ").strip()
+        if len(username) >= 3:
+            break
+        print("Username must be at least 3 characters.")
+    
+    while True:
+        password = getpass.getpass("Admin password (min 8 chars): ")
+        if len(password) >= 8:
+            password_confirm = getpass.getpass("Confirm password: ")
+            if password == password_confirm:
+                break
+            print("Passwords don't match. Try again.")
+        else:
+            print("Password must be at least 8 characters.")
+    
+    full_name = input("Full name (optional): ").strip() or None
+    
+    # Create admin user
+    print("\nCreating admin user...")
+    user, error = create_user(
+        email=email,
+        username=username,
+        password=password,
+        full_name=full_name,
+        role='admin',
+        is_verified=True
+    )
+    
+    if error:
+        print(f"Error creating admin: {error}")
+        return False
+    
+    # Set higher rate limits for admin
+    user.rate_limit_per_minute = 300
+    user.rate_limit_per_hour = 5000
+    user.rate_limit_per_day = 50000
+    
+    # Add all permissions
+    user.permissions = ['all']
+    
+    db.session.commit()
+    
+    print(f"\n✅ Admin user created successfully!")
+    print(f"   Email: {user.email}")
+    print(f"   Username: {user.username}")
+    print(f"   API Key: {user.api_key}")
+    print(f"\n📝 Save your API key securely. You can use it to authenticate API requests.")
+    print(f"\n🔐 Login at: http://localhost:5005/login")
+    print(f"📊 Admin dashboard: http://localhost:5005/admin/users")
+    
+    return True
+
+
+def init_database():
+    """Initialize the database with all tables"""
+    # Create Flask app
+    app = Flask(__name__)
+    
+    # Initialize configuration
+    init_config(app)
+    
+    # Initialize bcrypt
+    bcrypt.init_app(app)
+    
+    # Initialize database
+    init_db(app)
+    
+    with app.app_context():
+        print("Creating database tables...")
+        
+        # Import all models to ensure they're registered
+        from auth_models import User, LoginHistory, UserSession, RevokedToken
+        from database import Translation, Transcription, UserPreferences, UsageAnalytics, ApiKey
+        
+        # Create all tables
+        db.create_all()
+        print("✅ Database tables created successfully!")
+        
+        # Check if admin user already exists
+        admin_exists = User.query.filter_by(role='admin').first()
+        
+        if admin_exists:
+            print(f"\n⚠️  Admin user already exists: {admin_exists.username}")
+            # Skip creating new admin if running non-interactively
+            if not sys.stdin.isatty():
+                print("Running non-interactively, skipping admin user creation.")
+                return
+            create_new = input("Create another admin user? (y/n): ").lower().strip()
+            if create_new != 'y':
+                print("\nExiting without creating new admin.")
+                return
+        
+        # Create admin user
+        if not create_admin_user():
+            print("\n❌ Failed to create admin user.")
+            sys.exit(1)
+        
+        print("\n✨ Authentication system initialized successfully!")
+
+
+if __name__ == '__main__':
+    try:
+        init_database()
+    except KeyboardInterrupt:
+        print("\n\nSetup cancelled by user.")
+        sys.exit(0)
+    except Exception as e:
+        print(f"\n❌ Error during setup: {str(e)}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)