Overhaul SimDeck documentation for usage-focused guidance

[DjDeveloperr]

Summary

• Rewrote the docs around install, quick start, daily usage, troubleshooting, and inspector workflows
• Simplified the homepage and navigation to emphasize core features instead of internals
• Condensed CLI, API, extension, and contributor pages into shorter reference-style docs
• Kept the public routes and command surface aligned with the current implementation

Testing

• npm run docs:build passed
• npx prettier --check docs passed