Backup: nur Settings als Default + 4 Selektions/Flicker-Bugfixes

Backup:
- Neues Setting backupIncludeDownloads (Default aus) — Backup sichert
  standardmaessig NUR Einstellungen, nicht die Download-Liste/History.
- buildBackupPayload/planBackupImport (testbare backup-payload.ts): Export
  omittet session+history wenn Flag aus (explizites kind-Marker); Import folgt
  dem FILE-Inhalt, nicht dem lokalen Toggle.
- importBackup: settings-only -> frueher Return nach setSettings, KEIN stop/
  Queue-Wipe/Relaunch. Return {restored,relaunch,message}; main.ts gated den
  Auto-Relaunch auf relaunch. Renderer re-seeded settingsDraft bei !relaunch.

Bugfixes:
- Ctrl+A waehlte das ungefilterte Paket-Map -> Loeschen nach Suche traf
  versteckte Pakete. Jetzt visibleOrderIds (sichtbare Zeilen, inkl. Items).
- selectedIds nie geprunt bei Delta-Removal -> aufgeblaehte Counts. Neue pure
  pruneSelection (selection.ts) + Effect.
- link-status-dot conditional -> Dateiname sprang ~14px. Platzhalter-Slot.
- sortPackagesForDisplay sortierte aktive Pakete nach Live-Progress -> Reshuffle
  pro Tick. Jetzt stabile Queue-Reihenfolge je Gruppe (Anti-Flicker).

+17 Tests (backup-payload 9, selection 5, package-order anti-flicker 3).

src/main/backup-payload.ts

@@ -0,0 +1,77 @@
+import type { AppSettings, SessionState, HistoryEntry } from "../shared/types";
+
+export type BackupKind = "full" | "settings-only";
+
+export interface BackupPayload {
+  version: 2;
+  kind: BackupKind;
+  appVersion: string;
+  exportedAt: string;
+  settings: AppSettings;
+  session?: SessionState;
+  history?: HistoryEntry[];
+}
+
+export interface BuildBackupInput {
+  settings: AppSettings;
+  appVersion: string;
+  exportedAt: string;
+  /** Only bundled when includeDownloads is true. */
+  session: SessionState;
+  history: HistoryEntry[];
+}
+
+/**
+ * Build the backup payload. By default ("Download-Liste mitsichern" off) the
+ * payload contains ONLY settings — no session, no history. The download list is
+ * bundled solely when settings.backupIncludeDownloads is true. An explicit kind
+ * marker makes the import side unambiguous and survives hand-edited files.
+ */
+export function buildBackupPayload(input: BuildBackupInput): BackupPayload {
+  const includeDownloads = Boolean(input.settings.backupIncludeDownloads);
+  const base: BackupPayload = {
+    version: 2,
+    kind: includeDownloads ? "full" : "settings-only",
+    appVersion: input.appVersion,
+    exportedAt: input.exportedAt,
+    settings: input.settings
+  };
+  if (includeDownloads) {
+    base.session = input.session;
+    base.history = input.history;
+  }
+  return base;
+}
+
+export interface ImportPlan {
+  valid: boolean;
+  /** Restore the download list (session + history) and relaunch. */
+  restoreDownloads: boolean;
+  message: string;
+}
+
+/**
+ * Decide how to apply an imported backup based on what the FILE physically
+ * contains — NOT the local toggle. A backup without a session restores settings
+ * only (no queue wipe, no relaunch); a full backup (with session) restores the
+ * queue too. This way an old full backup still restores fully even if the local
+ * toggle is currently off, and a settings-only backup never disturbs a running
+ * queue.
+ */
+export function planBackupImport(parsed: unknown): ImportPlan {
+  if (!parsed || typeof parsed !== "object") {
+    return { valid: false, restoreDownloads: false, message: "Kein gültiges Backup (settings fehlen)" };
+  }
+  const record = parsed as Record<string, unknown>;
+  if (!record.settings || typeof record.settings !== "object") {
+    return { valid: false, restoreDownloads: false, message: "Kein gültiges Backup (settings fehlen)" };
+  }
+  const hasSession = Boolean(record.session) && typeof record.session === "object";
+  return {
+    valid: true,
+    restoreDownloads: hasSession,
+    message: hasSession
+      ? "Backup wiederhergestellt – App startet automatisch neu…"
+      : "Einstellungen wiederhergestellt"
+  };
+}