Revalidate completed items on startup, fix stale session data

Items incorrectly marked as "completed" by the old 50% recovery threshold
persist in the session file across updates. On startup, check all completed
items: if the file on disk is smaller than expected totalBytes, reset to
"queued" so it gets re-downloaded. Also reset items whose files are missing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/download-manager.ts

@@ -1074,6 +1074,7 @@ export class DownloadManager extends EventEmitter {
     this.recoverPostProcessingOnStartup();
     this.resolveExistingQueuedOpaqueFilenames();
     this.restoreTargetPathReservations();
+    this.revalidateCompletedItems();
     this.checkExistingRapidgatorLinks();
     void this.cleanupExistingExtractedArchives().catch((err) => logger.warn(`cleanupExistingExtractedArchives Fehler (constructor): ${compactErrorText(err)}`));
   }
@@ -3992,6 +3993,42 @@ export class DownloadManager extends EventEmitter {
     this.fixDuplicateSuffixFiles();
   }
 
+  /** Re-validate "completed" items on startup: if the file on disk is significantly
+   *  smaller than expected, the item was incorrectly marked completed (e.g. by the
+   *  old 50% recovery threshold). Reset to "queued" so it gets re-downloaded. */
+  private revalidateCompletedItems(): void {
+    let fixed = 0;
+    for (const item of Object.values(this.session.items)) {
+      if (item.status !== "completed") continue;
+      if (!item.targetPath || !item.totalBytes || item.totalBytes <= 0) continue;
+      try {
+        const stat = fs.statSync(item.targetPath);
+        if (stat.size < item.totalBytes - ALLOCATION_UNIT_SIZE) {
+          logger.warn(`revalidateCompleted: ${item.fileName} ist nur ${humanSize(stat.size)} statt ${humanSize(item.totalBytes)}, setze auf queued`);
+          item.status = "queued";
+          item.fullStatus = "Wartet";
+          item.downloadedBytes = stat.size;
+          item.progressPercent = Math.floor((stat.size / item.totalBytes) * 100);
+          item.speedBps = 0;
+          fixed += 1;
+        }
+      } catch {
+        // file doesn't exist — reset to queued so it gets re-downloaded
+        logger.warn(`revalidateCompleted: ${item.fileName} Datei nicht gefunden, setze auf queued`);
+        item.status = "queued";
+        item.fullStatus = "Wartet";
+        item.downloadedBytes = 0;
+        item.progressPercent = 0;
+        item.speedBps = 0;
+        fixed += 1;
+      }
+    }
+    if (fixed > 0) {
+      logger.info(`revalidateCompletedItems: ${fixed} Items korrigiert`);
+      this.persistSoon();
+    }
+  }
+
   /** Detect items whose targetPath has a " (N)" suffix from a previous bug and rename
    *  them back to the original filename if the original path is not claimed by another item. */
   private fixDuplicateSuffixFiles(): void {

src/renderer/App.tsx

@@ -5363,7 +5363,7 @@ interface PackageCardProps {
   selectedIds: Set<string>;
   columnOrder: string[];
   gridTemplate: string;
-  onSelect: (id: string, ctrlKey: boolean) => void;
+  onSelect: (id: string, ctrlKey: boolean, shiftKey: boolean) => void;
   onSelectMouseDown: (id: string, e: React.MouseEvent) => void;
   onSelectMouseEnter: (id: string) => void;
   onStartEdit: (packageId: string, packageName: string) => void;
@@ -5422,7 +5422,7 @@ const PackageCard = memo(function PackageCard({ pkg, items, packageSpeed, isFirs
       className={`package-card queue-package-card${pkg.enabled ? "" : " disabled-pkg"}${selectedIds.has(pkg.id) ? " pkg-selected" : ""}`}
       draggable
       onContextMenu={(e) => { e.preventDefault(); e.stopPropagation(); onContextMenu(pkg.id, undefined, e.clientX, e.clientY); }}
-      onClick={(e) => { if (e.ctrlKey) onSelect(pkg.id, true); }}
+      onClick={(e) => { if (e.ctrlKey || e.shiftKey) onSelect(pkg.id, e.ctrlKey, e.shiftKey); }}
       onMouseDown={(e) => onSelectMouseDown(pkg.id, e)}
       onMouseEnter={() => onSelectMouseEnter(pkg.id)}
       onDragStart={(event) => { event.stopPropagation(); onDragStart(pkg.id); }}
@@ -5504,7 +5504,7 @@ const PackageCard = memo(function PackageCard({ pkg, items, packageSpeed, isFirs
         {useExtractSplit && <div className="progress-ex" style={{ width: `${exProgress}%` }} />}
       </div>
       {!collapsed && items.filter((item) => !hideExtractedItems || !item.fullStatus?.startsWith("Entpackt")).map((item) => (
-        <div key={item.id} className={`item-row${selectedIds.has(item.id) ? " item-selected" : ""}`} style={{ gridTemplateColumns: gridTemplate }} onClick={(e) => { e.stopPropagation(); onSelect(item.id, e.ctrlKey); }} onMouseDown={(e) => { e.stopPropagation(); onSelectMouseDown(item.id, e); }} onMouseEnter={() => onSelectMouseEnter(item.id)} onContextMenu={(e) => { e.preventDefault(); e.stopPropagation(); onContextMenu(pkg.id, item.id, e.clientX, e.clientY); }}>
+        <div key={item.id} className={`item-row${selectedIds.has(item.id) ? " item-selected" : ""}`} style={{ gridTemplateColumns: gridTemplate }} onClick={(e) => { e.stopPropagation(); onSelect(item.id, e.ctrlKey, e.shiftKey); }} onMouseDown={(e) => { e.stopPropagation(); onSelectMouseDown(item.id, e); }} onMouseEnter={() => onSelectMouseEnter(item.id)} onContextMenu={(e) => { e.preventDefault(); e.stopPropagation(); onContextMenu(pkg.id, item.id, e.clientX, e.clientY); }}>
           {columnOrder.map((col) => {
             switch (col) {
               case "name": return (