feat: Desktop Sync Client (Tauri) - Grundgeruest

Tauri 2 Desktop-Client mit:

Rust-Backend:
- MiniCloudApi: Login, Token-Refresh, Upload, Download, Sync-Tree,
  Sync-Changes, File-Locking (Lock/Unlock/Heartbeat)
- SyncEngine: Full-Sync (Server-Tree vs. lokales Dateisystem),
  Delta-Sync (nur Aenderungen seit letztem Sync), bidirektionaler
  Abgleich mit SHA-256 Checksummen, Ordner-Erstellung,
  Lock-Status-Pruefung vor Upload, Konflikt-Erkennung
- FileWatcher: Filesystem-Watcher (notify crate) fuer Echtzeit-
  Erkennung lokaler Aenderungen, filtert temp/hidden files

Vue-Frontend:
- Login-Screen: Server-URL, Benutzername, Passwort
- Main-Screen: Sync-Ordner setzen, Sync starten, Dateiliste mit
  Lock-Status, Sync-Protokoll
- Dark-Mode Support

Tauri-Kommandos: login, set_sync_dir, start_sync, delta_sync,
  get_status, get_file_tree

Zum Bauen (Linux):
  sudo apt install libwebkit2gtk-4.1-dev libgtk-3-dev
  cd clients/desktop && npm install && npm run tauri build

Windows/Mac: Tauri Voraussetzungen installieren, dann gleicher Befehl

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

clients/desktop/vite.config.js

@@ -0,0 +1,31 @@
+import { defineConfig } from "vite";
+import vue from "@vitejs/plugin-vue";
+
+const host = process.env.TAURI_DEV_HOST;
+
+// https://vite.dev/config/
+export default defineConfig(async () => ({
+  plugins: [vue()],
+
+  // Vite options tailored for Tauri development and only applied in `tauri dev` or `tauri build`
+  //
+  // 1. prevent Vite from obscuring rust errors
+  clearScreen: false,
+  // 2. tauri expects a fixed port, fail if that port is not available
+  server: {
+    port: 1420,
+    strictPort: true,
+    host: host || false,
+    hmr: host
+      ? {
+          protocol: "ws",
+          host,
+          port: 1421,
+        }
+      : undefined,
+    watch: {
+      // 3. tell Vite to ignore watching `src-tauri`
+      ignored: ["**/src-tauri/**"],
+    },
+  },
+}));