docs: use OSS plugin for Capacitor live updates

[riderx]

What changed

This updates the Quasar Capacitor live updates guide to use @capgo/capacitor-updater instead of the Capawesome live update plugin who require subscription.

The guide now covers:

• installing the Capgo updater plugin
• configuring a manual, self-hosted update flow
• calling notifyAppReady()
• downloading and staging a bundle from a custom update endpoint
• creating the Quasar web bundle with quasar build --skip-pkg
• zipping the bundle with the Capgo CLI
• using a free self-hosted path, with Capgo Cloud mentioned as the shared hosted option at the end

Why

Capgo provides an open-source updater plugin and a self-hosted path for teams that want to manage their own update infrastructure. This gives Quasar Capacitor users a free/manual live-update path while still leaving the hosted option available.

Validation

• pnpm install --frozen-lockfile
• pnpm --filter quasar build
• pnpm prepare:types
• pnpm --filter app-vite-playground-js exec quasar prepare
• pnpm --filter app-vite-playground-ts exec quasar prepare
• pnpm lint:check

Note: local commands emitted workspace Node engine warnings because this machine is running Node v25.9.0, while several Quasar packages request Node 22/24/26+ ranges. The final lint check passed.