docs: refresh wiki for v0.1.1 stable and roadmap
Add full wiki: 13 pages + sidebar/footer + screenshots Pages: Home, Features, Installation, Getting Started, Architecture, Roadmap, Troubleshooting, Packaging and Releases, Development, Contributing, About, Feedback, plus _Sidebar and _Footer. Content cross-checked against all release notes (v0.1.0 through v0.1.1-beta.6) and the current source: Settings is a five-section sidebar (incl. Diagnostics and Data), strict auto-close is opt-in, three built-in sound themes, real beta asset names, Steam/Proton support, native C helpers and the watchdog supervisor.