feat(2.0): Phase 0 — Greenfield-Skeleton (FastAPI + React/shadcn)

Backend: FastAPI mit /api/health + /api/models (read-only aus llama-swap
config, Logik aus v1 portiert). Frontend: Vite + React + Tailwind v4 +
shadcn-Style App-Shell mit Cmd+K, Dark-default, PWA-Manifest; Modelle-View
live aus /api/models. Deploy-Geruest (systemd-Unit :9001, build/deploy-
Skripte, NOPASSWD-sudoers, kein Klartext-Passwort).

Verifiziert: Backend-Endpunkte + Frontend-Build + gerenderte Shell.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/utils.ts

@@ -0,0 +1,6 @@
+import { clsx, type ClassValue } from "clsx"
+import { twMerge } from "tailwind-merge"
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}