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/004_rollback_timescaledb.sql

@@ -0,0 +1,52 @@
+-- Rollback Migration: Remove TimescaleDB Time-Series Tables
+-- Created: 2025-01-15
+-- Description: Drops all TimescaleDB hypertables, continuous aggregates, and policies
+-- WARNING: This will permanently delete all time-series analytics data!
+
+-- ============================================================================
+-- Step 1: Remove Continuous Aggregate Policies
+-- ============================================================================
+SELECT remove_continuous_aggregate_policy('website_metrics_hourly_agg', if_exists => TRUE);
+SELECT remove_continuous_aggregate_policy('product_metrics_daily_agg', if_exists => TRUE);
+
+-- ============================================================================
+-- Step 2: Drop Continuous Aggregates (Materialized Views)
+-- ============================================================================
+DROP MATERIALIZED VIEW IF EXISTS website_metrics_hourly_agg CASCADE;
+DROP MATERIALIZED VIEW IF EXISTS product_metrics_daily_agg CASCADE;
+
+-- ============================================================================
+-- Step 3: Remove Retention Policies
+-- ============================================================================
+SELECT remove_retention_policy('time_series_events', if_exists => TRUE);
+SELECT remove_retention_policy('website_metrics_hourly', if_exists => TRUE);
+SELECT remove_retention_policy('product_metrics_daily', if_exists => TRUE);
+
+-- ============================================================================
+-- Step 4: Drop Hypertables (this will drop the tables and all chunks)
+-- ============================================================================
+DROP TABLE IF EXISTS time_series_events CASCADE;
+DROP TABLE IF EXISTS website_metrics_hourly CASCADE;
+DROP TABLE IF EXISTS product_metrics_daily CASCADE;
+
+-- ============================================================================
+-- Step 5: Drop TimescaleDB Extension (Optional)
+-- ============================================================================
+-- Note: Only drop extension if no other hypertables exist
+-- Uncomment the following line if you want to completely remove TimescaleDB
+-- DROP EXTENSION IF EXISTS timescaledb CASCADE;
+
+-- ============================================================================
+-- Rollback Complete
+-- ============================================================================
+DO $$
+BEGIN
+  RAISE NOTICE '=================================================================';
+  RAISE NOTICE 'TimescaleDB Rollback Complete';
+  RAISE NOTICE 'Dropped hypertables: time_series_events, website_metrics_hourly, product_metrics_daily';
+  RAISE NOTICE 'Dropped continuous aggregates: website_metrics_hourly_agg, product_metrics_daily_agg';
+  RAISE NOTICE 'Removed all retention policies';
+  RAISE NOTICE 'Note: TimescaleDB extension was NOT dropped (may be used by other tables)';
+  RAISE NOTICE '=================================================================';
+END $$;
+