Enhance Local Server Discovery UI & Mobile Testing Flow

[RZDESIGN]

Summary

This PR significantly improves the local development experience by overhauling the "Connect to Server" modal. It introduces automatic local server discovery, a polished HYTOPIA-branded UI, and a seamless QR code flow to make testing local dev servers on mobile devices effortless.

Changes

• Auto-Discovery & QR Codes:
  • Added a /__hytopia/local-ip endpoint to the Vite dev server to reliably auto-detect the developer's LAN IP.
  • The server health check (/) now also returns local network addresses.
  • Automatically generates a QR code pointing to hytopia.com/play/?join=... (mapping the private IP to our cert-compatible wildcard hostname) so developers can instantly join their local server from a phone or tablet.
• UI/UX Polish:
  • Replaced the basic prompt and error alerts with a smooth, multi-state modal (Searching → Found → Manual Entry).
  • Added a HYTOPIA-gradient loading spinner while searching for local servers.
  • Implemented a persistent, pulsing gradient glow anchored to the bottom of the viewport.
  • Added the HYTOPIA square logo to the overlay.
  • Styled the "SERVER FOUND / LET'S PLAY" headers with custom gradient text.
  • Created a glowing, hovering "Play" button for desktop connections.
  • Added smooth CSS fade/slide-in animations (hytopia-fade-in-up) for state transitions.
• Graceful Error Handling:
  • Replaced the abrupt "Could not connect" alert popup with a seamless transition back to the "Looking for local server" spinner.
  • If the server disconnects mid-game, the client intelligently drops the ?join= param and returns to the glowing search state instead of getting stuck in a refresh loop.
• Dependencies: Added qrcode and @types/qrcode for canvas-based QR generation.

Test Plan

• Run npm run dev in the client and hytopia start for the server.
• Verify the initial state shows the gradient loading spinner.
• Verify the modal smoothly transitions to the "SERVER FOUND" view once the server is healthy.
• Scan the QR code with a mobile device on the same Wi-Fi network and confirm it successfully connects to the local dev server.
• Stop the local server while the "Found" modal is open, and verify it gracefully falls back to the searching spinner.
• Connect to the server, then kill the server. Verify the page reloads and drops you cleanly back into the search spinner.
• Click "Other address" and ensure the manual IP fallback works and correctly maps raw IPs to the *.dns-is-boring... hostname.

[RZDESIGN]

Schermopname.2026-03-04.om.22.08.32.mp4

[web3dev1337]

Noting #5 has a similar use, so should be compared for best solution