feat: integrate First8 Marketing hyper-personalization system

Enhanced Umami Analytics with First8 Marketing integration for
hyper-personalized recommendation engine.

Database Enhancements:
- PostgreSQL 17 with Apache AGE 1.6.0 (graph database)
- TimescaleDB 2.23.0 (time-series optimization)
- Extended schema for WooCommerce event tracking
- Custom tables for recommendation engine integration

Features Added:
- Real-time ETL pipeline to recommendation engine
- Extended event tracking (WordPress + WooCommerce)
- Graph database for relationship mapping
- Time-series optimization for analytics queries
- Custom migrations for hyper-personalization

Documentation:
- Updated README with integration details
- Added system architecture documentation
- Documented data flow and components
- Preserved original Umami Software credits

Integration Components:
- First8 Marketing Track plugin (event tracking)
- Recommendation Engine (ML backend)
- First8 Marketing Recommendation Engine plugin (presentation)

Status: Production-ready
Version: Based on Umami latest + First8 Marketing enhancements

db/postgresql/rollback/002_rollback_recommendation_tables.sql

@@ -0,0 +1,22 @@
+-- Rollback Migration: Remove Recommendation Engine Tables
+-- Created: 2025-01-15
+-- Description: Drops all recommendation engine tables and their dependencies
+-- WARNING: This will permanently delete all recommendation data, user profiles, and ML model registry!
+
+-- Drop tables in reverse order of dependencies
+-- Drop recommendations table first (has foreign key to website)
+DROP TABLE IF EXISTS recommendations CASCADE;
+
+-- Drop user_profiles table (has foreign key to website)
+DROP TABLE IF EXISTS user_profiles CASCADE;
+
+-- Drop ml_models table (no dependencies)
+DROP TABLE IF EXISTS ml_models CASCADE;
+
+-- Log rollback completion
+DO $$
+BEGIN
+  RAISE NOTICE 'Rollback complete: All recommendation engine tables removed';
+  RAISE NOTICE 'Dropped tables: recommendations, user_profiles, ml_models';
+END $$;
+