feat: scope + un-bundle the plugin; @unom/ui SPA; custom-emulator editor

Reliability + correctness pass on the packaging and UI.

Packaging — drop the self-contained bundle:
- Rename to `@punktfunk/plugin-rom-manager` (scoped). An unscoped package can't
  be split across registries, which is the only reason bundling effect + the SDK
  into every plugin seemed necessary. Scoped names resolve from one scope-map, so
  the plugin depends on `@punktfunk/host` + `effect` as SHARED (hoisted) deps —
  no duplication, no ~1 MB effect copy per plugin. Build is back to plain `tsc`.
  (Runner-side discovery of `@punktfunk/plugin-*` shipped in @punktfunk/host 0.1.1.)

UI — use the console's design system so it reads as family:
- SPA rebuilt on @unom/style tokens + Tailwind v4 + the console's exact theme
  (violet chrome, Geist, card/button vocabulary). Build-time only → static assets
  in dist/ui, no @unom runtime dep. Skips @unom/ui's AnimatedButton/Card, which
  statically import ~7 MB of UI sound assets — same look, 416 KB dist/ui.
- Add a custom-emulator editor (Emulators page) writing config.emulators — you can
  now add a launcher Punktfunk doesn't ship a definition for.
- Fix brand capitalization to "Punktfunk" in all UI copy + docs.

Install docs + CI updated for the scoped `bun add @punktfunk/plugin-rom-manager`
flow. 48 engine tests green; backend + UI typecheck + biome clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ui/src/main.tsx

@@ -1,3 +1,5 @@
+import "@fontsource-variable/geist";
+import { Toaster } from "@unom/ui/toast";
 import { StrictMode } from "react";
 import { createRoot } from "react-dom/client";
 import { App } from "./App.js";
@@ -6,5 +8,6 @@ import "./styles.css";
 createRoot(document.getElementById("root")!).render(
 	<StrictMode>
 		<App />
+		<Toaster />
 	</StrictMode>,
 );