fix: make Reverb/Echo config runtime-injected instead of Vite build-time

[maartenbode]

Summary

• Inject Reverb config (key, port, scheme) from Laravel backend into the HTML via meta tags at runtime, instead of baking VITE_REVERB_* env vars into the JS bundle at Vite build time
• Remove VITE_REVERB_* variables from .env.example and docs
• Ignore auto-generated Wayfinder resources/js/actions directory in ESLint config

This makes the Docker image environment-agnostic — the same image works in any deployment without rebuilding.