feat(site): modernize interactive UserALE 2.5 demo, expand Distill & deployment docs, and add Playwright E2E test

[brucearctor]

Summary

1. Interactive UserALE 2.5 Live Demo (site/_includes/useralejsDemo.html, site/js/userale-demo.min.js, site/_sass/_userale.scss):
   • Replaced the legacy 2017 userale-demo.min.js bundle with the UserALE 2.5 IIFE bundle and exposed toOtlpExportLogsServiceRequest, toOtlpLogRecord, toProtoLogBatch, and toProtoUserALELog on window.userale in products/userale/packages/flagon-userale/src/main.ts.
   • Added a live Wire Format Switcher (UserALE JSON | OTLP/JSON (OpenTelemetry) | Protobuf v1 JSON), Rage-Click trigger (RageClickDetector), DOM Mutation trigger (MutationCollector), and PII-Redacted input (data-userale-redact="true").
2. Playwright E2E Verification (products/userale/test/spec/04-package-site-demo.spec.ts & products/userale/example/server/server.js):
   • Added an automated Playwright E2E test (Apache-2.0 licensed) that mounts site/_includes/useralejsDemo.html and site/js/userale-demo.min.js and verifies interaction capture, live wire-format re-serialization (UserALE JSON, OTLP/JSON, Protobuf v1 JSON), rage-click detection, DOM mutation capture, and data-userale-redact PII scrubbing across Chromium and Firefox.
3. Expanded Distill Documentation (site/_docs/distill/):
   • Added /docs/distill/behavioral/ (site/_docs/distill/behavioral.md) covering detect_rage_clicks, detect_dead_clicks, detect_dom_thrash, frustration_score, click_heatmap_data, plot_click_heatmap, scroll_depth_summary, correlate_by_trace, and extract_replay_envelopes.
   • Added /docs/distill/graphs/ (site/_docs/distill/graphs.md) covering createDiGraph, transition_matrix, sankey, and funnel.
   • Added /docs/distill/segmentation/ (site/_docs/distill/segmentation.md) covering multi-format ingestion (extract_logs, UserAleSchema), session_summary, click_rate, and Segment/Segments slicing.
4. Reference Architectures & Deployments Guide (site/_docs/deployments.md):
   • Added /docs/deployments/ covering the 4 Docker Compose reference stacks (OpenTelemetry + Grafana Loki/Tempo, OpenSearch + Dashboards, Apache Lakehouse with Kafka/Iceberg/Spark/Superset, and ELK).
5. Modernized Site Build (site/Dockerfile, site/Gemfile, site/build.sh, site/README.md):
   • Upgraded site/Dockerfile from phusion/passenger-full:3.0.7 to ruby:3.3-slim and added webrick to site/Gemfile for Ruby 3.x jekyll serve support.