Add comprehensive database rebuild capability with complete unified schema

Features:
- Complete SQL schema file (000_complete_schema.sql) for full database rebuild
- Unified authentication system with UUID-based users, API keys, refresh tokens
- All platform tables: users, agents, workflows, tasks, executions, metrics, alerts
- Comprehensive indexing strategy for performance optimization
- Automated rebuild scripts (Python and Shell) with Docker integration
- Detailed documentation with usage instructions and troubleshooting

Schema capabilities:
✅ UUID-based design for scalability and consistency
✅ Complete authentication: JWT, API keys, password hashing, token blacklisting
✅ Agent management: Ollama and CLI agents with performance metrics
✅ Workflow orchestration: n8n integration with execution tracking
✅ Task management: Priority-based assignment and status tracking
✅ Monitoring: System alerts, performance metrics, health checks
✅ Default users: admin and developer accounts for immediate access

This provides a single-command database rebuild capability that creates
the complete Hive platform schema from scratch, resolving all previous
schema conflicts and providing a clean foundation for authentication
and full platform functionality.

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

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

backend/scripts/rebuild_database.py

@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+"""
+Database rebuild script for Hive platform.
+Completely rebuilds the database schema from scratch using the unified schema.
+"""
+
+import os
+import sys
+import logging
+import psycopg2
+from pathlib import Path
+
+# Configure logging
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s - %(levelname)s - %(message)s"
+)
+logger = logging.getLogger(__name__)
+
+def get_database_config():
+    """Get database configuration from environment variables."""
+    return {
+        'host': os.getenv('DB_HOST', 'localhost'),
+        'port': os.getenv('DB_PORT', '5432'),
+        'database': os.getenv('DB_NAME', 'hive'),
+        'user': os.getenv('DB_USER', 'postgres'),
+        'password': os.getenv('DB_PASSWORD', 'hive123'),
+    }
+
+def execute_sql_file(connection, sql_file_path):
+    """Execute an SQL file against the database."""
+    try:
+        with open(sql_file_path, 'r') as file:
+            sql_content = file.read()
+        
+        with connection.cursor() as cursor:
+            cursor.execute(sql_content)
+        
+        connection.commit()
+        logger.info(f"Successfully executed {sql_file_path}")
+        return True
+        
+    except Exception as e:
+        logger.error(f"Failed to execute {sql_file_path}: {e}")
+        connection.rollback()
+        return False
+
+def main():
+    """Main function to rebuild the database."""
+    logger.info("🔄 Starting Hive database rebuild...")
+    
+    # Get database configuration
+    db_config = get_database_config()
+    logger.info(f"Connecting to database: {db_config['host']}:{db_config['port']}/{db_config['database']}")
+    
+    # Connect to database
+    try:
+        connection = psycopg2.connect(**db_config)
+        logger.info("✅ Connected to database successfully")
+    except Exception as e:
+        logger.error(f"❌ Failed to connect to database: {e}")
+        sys.exit(1)
+    
+    try:
+        # Path to the complete schema file
+        schema_file = Path(__file__).parent.parent / "migrations" / "000_complete_schema.sql"
+        
+        if not schema_file.exists():
+            logger.error(f"❌ Schema file not found: {schema_file}")
+            sys.exit(1)
+        
+        logger.info(f"📄 Using schema file: {schema_file}")
+        
+        # Execute the complete schema
+        logger.info("🏗️  Rebuilding database schema...")
+        if execute_sql_file(connection, schema_file):
+            logger.info("✅ Database schema rebuilt successfully!")
+            
+            # Verify the rebuild
+            with connection.cursor() as cursor:
+                cursor.execute("SELECT COUNT(*) FROM users;")
+                user_count = cursor.fetchone()[0]
+                
+                cursor.execute("SELECT COUNT(*) FROM pg_tables WHERE schemaname = 'public';")
+                table_count = cursor.fetchone()[0]
+                
+                logger.info(f"📊 Database verification:")
+                logger.info(f"   - Tables created: {table_count}")
+                logger.info(f"   - Initial users: {user_count}")
+                
+                if user_count >= 2:
+                    logger.info("🔐 Default users created successfully")
+                    logger.warning("⚠️  SECURITY: Change default passwords in production!")
+                else:
+                    logger.warning("⚠️  Warning: Expected at least 2 initial users")
+                
+        else:
+            logger.error("❌ Failed to rebuild database schema")
+            sys.exit(1)
+            
+    except Exception as e:
+        logger.error(f"❌ Unexpected error during rebuild: {e}")
+        sys.exit(1)
+        
+    finally:
+        connection.close()
+        logger.info("🔌 Database connection closed")
+    
+    logger.info("🎉 Hive database rebuild completed successfully!")
+    logger.info("🚀 Ready for authentication and full platform functionality")
+
+if __name__ == "__main__":
+    main()