feat: implement two-step Freigabe→Zahlung workflow

Adds a payment step after document approval: PM_Freigabe approves
(Field 15 = "freigegeben"), then PM_Zahlung can mark as paid (Field 16).

- Backend: VIEW_ZAHLUNG permission mapped to PM_Zahlung OIDC group
- Backend: ZahlungModule with endpoints to list documents by filter
  (ausstehend/freigegeben/alle), set Field 16, fetch options from Paperless
- Backend: setZahlung() throws ForbiddenException if Field 15 ≠ "freigegeben"
- Frontend: /zahlung route with 3-way filter, two status columns (Freigabe + Zahlung)
- Frontend: "Zahlung verbuchen" button disabled with tooltip for non-approved docs
- Frontend: Zahlung menu item with EuroOutlined icon

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

paperless-backend/src/app.module.ts

@@ -20,6 +20,7 @@ import { UserSettingsModule } from './user-settings/user-settings.module';
 import { LabelPrintAgentModule } from './label-print-agent/label-print-agent.module';
 import { AgrarmonitorModule } from './agrarmonitor/agrarmonitor.module';
 import { FreigabeModule } from './freigabe/freigabe.module';
+import { ZahlungModule } from './zahlung/zahlung.module';
 import { DailyDigestModule } from './daily-digest/daily-digest.module';
 import * as path from 'path';
 
@@ -52,6 +53,7 @@ import * as path from 'path';
     LabelPrintAgentModule,
     AgrarmonitorModule,
     FreigabeModule,
+    ZahlungModule,
     DailyDigestModule,
   ],
 })

paperless-backend/src/auth/permissions.enum.ts

@@ -6,6 +6,7 @@ export const Permission = {
   VIEW_SCANNER: 'VIEW_SCANNER',
   MANAGE_SETTINGS: 'MANAGE_SETTINGS',
   VIEW_FREIGABE: 'VIEW_FREIGABE',
+  VIEW_ZAHLUNG: 'VIEW_ZAHLUNG',
 } as const;
 
 export type Permission = (typeof Permission)[keyof typeof Permission];
@@ -27,6 +28,7 @@ export function mapGroupsToPermissions(
     permissions.add(Permission.VIEW_SCANNER);
     permissions.add(Permission.MANAGE_SETTINGS);
     permissions.add(Permission.VIEW_FREIGABE);
+    permissions.add(Permission.VIEW_ZAHLUNG);
     return Array.from(permissions);
   }
 
@@ -36,6 +38,7 @@ export function mapGroupsToPermissions(
   if (groups.includes('PM_Posteingang')) permissions.add(Permission.VIEW_INBOX);
   if (groups.includes('PM_Scanner')) permissions.add(Permission.VIEW_SCANNER);
   if (groups.includes('PM_Freigabe')) permissions.add(Permission.VIEW_FREIGABE);
+  if (groups.includes('PM_Zahlung')) permissions.add(Permission.VIEW_ZAHLUNG);
 
   return Array.from(permissions);
 }

paperless-backend/src/zahlung/zahlung.controller.ts

@@ -0,0 +1,36 @@
+import { Controller, Get, Put, Param, Body, Query } from '@nestjs/common';
+import { RequirePermissions } from '../auth/permissions.decorator';
+import { Permission } from '../auth/permissions.enum';
+import { ZahlungService, type ZahlungFilter } from './zahlung.service';
+
+@Controller('api/zahlung')
+@RequirePermissions(Permission.VIEW_ZAHLUNG)
+export class ZahlungController {
+  constructor(private readonly zahlungService: ZahlungService) {}
+
+  @Get('documents')
+  getDocuments(
+    @Query('page') page = '1',
+    @Query('pageSize') pageSize = '25',
+    @Query('filter') filter: ZahlungFilter = 'ausstehend',
+  ) {
+    return this.zahlungService.getZahlungDocuments(
+      parseInt(page, 10),
+      Math.min(parseInt(pageSize, 10), 100),
+      filter,
+    );
+  }
+
+  @Put('documents/:id/zahlung')
+  setZahlung(
+    @Param('id') id: string,
+    @Body('value') value: string | null,
+  ) {
+    return this.zahlungService.setZahlung(parseInt(id, 10), value ?? null);
+  }
+
+  @Get('options')
+  getOptions() {
+    return this.zahlungService.getZahlungOptions();
+  }
+}

paperless-backend/src/zahlung/zahlung.module.ts

@@ -0,0 +1,13 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { DocumentType } from '../database/entities/document-type.entity';
+import { PaperlessModule } from '../paperless/paperless.module';
+import { ZahlungController } from './zahlung.controller';
+import { ZahlungService } from './zahlung.service';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([DocumentType]), PaperlessModule],
+  controllers: [ZahlungController],
+  providers: [ZahlungService],
+})
+export class ZahlungModule {}

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

@@ -0,0 +1,124 @@
+import { Injectable, Logger, ForbiddenException } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { DocumentType } from '../database/entities/document-type.entity';
+import { PaperlessService } from '../paperless/paperless.service';
+
+const FREIGABE_FIELD_ID = 15;
+const ZAHLUNG_FIELD_ID = 16;
+const FREIGABE_WERT_FREIGEGEBEN = 'freigegeben';
+
+export type ZahlungFilter = 'ausstehend' | 'freigegeben' | 'alle';
+
+@Injectable()
+export class ZahlungService {
+  private readonly logger = new Logger(ZahlungService.name);
+
+  constructor(
+    @InjectRepository(DocumentType)
+    private readonly documentTypeRepo: Repository<DocumentType>,
+    private readonly paperlessService: PaperlessService,
+  ) {}
+
+  async getZahlungDocuments(page: number, pageSize: number, filter: ZahlungFilter) {
+    const docTypes = await this.documentTypeRepo.find({
+      where: { FreigabeErforderlich: true as any },
+    });
+
+    if (docTypes.length === 0) {
+      return { count: 0, results: [] };
+    }
+
+    const docTypeIds = docTypes.map((dt) => dt.DocumentTypeId).join(',');
+
+    const params: Record<string, any> = {
+      page: 1,
+      page_size: 9999,
+      document_type__id__in: docTypeIds,
+      ordering: '-created',
+      truncate_content: true,
+    };
+
+    let allDocs: any[];
+    try {
+      const result = await this.paperlessService.getDocuments(params);
+      allDocs = result.results ?? [];
+    } catch (err: any) {
+      this.logger.warn('Fehler beim Laden der Belege für Zahlung', err?.message);
+      return { count: 0, results: [] };
+    }
+
+    const filtered = this.applyFilter(allDocs, filter);
+    const start = (page - 1) * pageSize;
+    return {
+      count: filtered.length,
+      results: filtered.slice(start, start + pageSize),
+    };
+  }
+
+  private applyFilter(docs: any[], filter: ZahlungFilter): any[] {
+    if (filter === 'alle') return docs;
+
+    return docs.filter((doc: any) => {
+      const freigabeValue = this.getCfValue(doc, FREIGABE_FIELD_ID);
+      const istFreigegeben = freigabeValue === FREIGABE_WERT_FREIGEGEBEN;
+
+      if (filter === 'freigegeben') return istFreigegeben;
+
+      // 'ausstehend': freigegeben aber noch nicht bezahlt
+      const zahlungValue = this.getCfValue(doc, ZAHLUNG_FIELD_ID);
+      return istFreigegeben && !zahlungValue;
+    });
+  }
+
+  private getCfValue(doc: any, fieldId: number): string | null {
+    const cf = (doc.custom_fields ?? []).find((f: any) => f.field === fieldId);
+    if (!cf || cf.value === null || cf.value === undefined || cf.value === '') return null;
+    if (typeof cf.value === 'object') {
+      return String(cf.value?.id ?? cf.value?.value ?? cf.value?.label ?? '') || null;
+    }
+    return String(cf.value);
+  }
+
+  async setZahlung(documentId: number, value: string | null) {
+    const doc = await this.paperlessService.getDocument(documentId);
+
+    const freigabeValue = this.getCfValue(doc, FREIGABE_FIELD_ID);
+    if (freigabeValue !== FREIGABE_WERT_FREIGEGEBEN) {
+      throw new ForbiddenException(
+        'Zahlung kann nur für freigegebene Belege gesetzt werden',
+      );
+    }
+
+    const customFields: any[] = [...(doc.custom_fields ?? [])];
+    const existing = customFields.find((f: any) => f.field === ZAHLUNG_FIELD_ID);
+    if (existing) {
+      existing.value = value;
+    } else if (value !== null && value !== '') {
+      customFields.push({ field: ZAHLUNG_FIELD_ID, value });
+    }
+
+    await this.paperlessService.updateDocument(documentId, { custom_fields: customFields });
+    return { success: true };
+  }
+
+  async getZahlungOptions(): Promise<{ id: string; label: string }[]> {
+    const fields = await this.paperlessService.getCustomFields();
+    const field = (fields as any[]).find((f: any) => f.id === ZAHLUNG_FIELD_ID);
+    if (!field) return [];
+
+    const rawOptions: any[] = field.extra_data?.select_options ?? [];
+    return rawOptions
+      .filter((o) => o !== null && o !== undefined && o !== '')
+      .map((o) => {
+        if (typeof o === 'object') {
+          return {
+            id: String(o.id ?? o.value ?? o.label ?? ''),
+            label: String(o.label ?? o.name ?? o.id ?? ''),
+          };
+        }
+        return { id: String(o), label: String(o) };
+      })
+      .filter((o) => o.id !== '');
+  }
+}