feat: add functionality to manually split documents at specific pages via the UI and API

paperless-backend/src/inbox/inbox.service.ts

@@ -21,6 +21,7 @@ export interface InboxFile {
   source: InboxSource;
   pageCount: number;
   deletedPages: number[];
+  manualSplitPages: number[];
   rotations: Record<string, number>;
   barcodes: MatchedBarcode[];
   createdAt: string;
@@ -60,6 +61,7 @@ export class InboxService {
         source: doc.Source,
         pageCount: doc.PageCount,
         deletedPages: [...(doc.DeletedPages ?? [])].sort((a, b) => a - b),
+        manualSplitPages: [...(doc.ManualSplitPages ?? [])].sort((a, b) => a - b),
         rotations: { ...(doc.Rotations ?? {}) },
         barcodes: await this.barcodeScanner.getMatched(doc),
         createdAt: doc.CreatedAt.toISOString(),
@@ -142,7 +144,7 @@ export class InboxService {
   }
 
   /**
-   * Setzt alle markierten Bearbeitungen (DeletedPages, Rotations) zurück.
+   * Setzt alle markierten Bearbeitungen (DeletedPages, Rotations, ManualSplitPages) zurück.
    */
   async resetEdits(id: string, preferredUsername: string | null): Promise<void> {
     const { doc } = await this.resolveDocument(id, preferredUsername);
@@ -155,9 +157,31 @@ export class InboxService {
       doc.Rotations = {};
       changed = true;
     }
+    if (doc.ManualSplitPages && doc.ManualSplitPages.length > 0) {
+      doc.ManualSplitPages = [];
+      changed = true;
+    }
     if (changed) await this.documentRepo.save(doc);
   }
 
+  /**
+   * Setzt oder entfernt einen manuellen Trennpunkt vor der angegebenen Seite.
+   */
+  async toggleManualSplit(id: string, page: number, preferredUsername: string | null): Promise<void> {
+    const { doc } = await this.resolveDocument(id, preferredUsername);
+    if (!Number.isInteger(page) || page < 2 || page > doc.PageCount) {
+      throw new BadRequestException('Ungültige Seitennummer für Trennung');
+    }
+    const splits = new Set<number>(doc.ManualSplitPages ?? []);
+    if (splits.has(page)) {
+      splits.delete(page);
+    } else {
+      splits.add(page);
+    }
+    doc.ManualSplitPages = Array.from(splits).sort((a, b) => a - b);
+    await this.documentRepo.save(doc);
+  }
+
   async deleteDocument(id: string, preferredUsername: string | null): Promise<void> {
     const { doc } = await this.resolveDocument(id, preferredUsername);
     const dir = this.pageCache.documentDir(doc.Id);