docs(wiki): publish the engineering reference wiki Twenty pages covering the v2 architecture, the wire protocol, the server bus, the bundle client, consumer engines and the operational surface, plus a sidebar and footer for navigation. The wiki is positioned as the engineering reference and deliberately does not duplicate docs.eventoframework.com, which owns the tutorial path. Each page states where the repository holds the authoritative version of the material so the two cannot silently diverge. Content is derived from .claude/ARCHITECTURE.md, CHANGELOG.md, CONTRIBUTING.md and the sources themselves; dependency versions are taken from build.gradle rather than the prose docs, which still record the pre-2.2.0 Spring Boot 3.5.5 toolchain.