feat: add Steuertags concept to separate workflow from content tags

- New steuertag_ids setting to mark tags as workflow-only (not editable)
- DocumentEditModal shows only content tags (non-Steuertags) as editable chips
- Backend preserves Steuertags when saving document tag changes
- ManuellBearbeitenPage renders content tag chips under document title
- New Steuertags settings tab with multi-select and color preview

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

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

@@ -29,6 +29,10 @@ import { Task } from '../database/entities/task.entity';
 import { Document } from '../database/entities/document.entity';
 import { DocumentField } from '../database/entities/document-field.entity';
 import { DocumentType } from '../database/entities/document-type.entity';
+import { Setting } from '../database/entities/setting.entity';
+
+/** Setting.Tag-Schlüssel für die manuell gepflegte Steuertag-Liste */
+export const STEUERTAG_SETTING_KEY = 'steuertag_ids';
 
 @Controller('api/paperless')
 export class PaperlessController {
@@ -44,8 +48,26 @@ export class PaperlessController {
     private readonly documentFieldRepo: Repository<DocumentField>,
     @InjectRepository(DocumentType)
     private readonly documentTypeRepo: Repository<DocumentType>,
+    @InjectRepository(Setting)
+    private readonly settingRepo: Repository<Setting>,
   ) {}
 
+  /** Liest die als Steuertags markierten Tag-IDs aus den Einstellungen. */
+  private async getSteuertagIds(): Promise<number[]> {
+    const setting = await this.settingRepo.findOneBy({
+      Tag: STEUERTAG_SETTING_KEY,
+    });
+    return (setting?.Wert ?? '')
+      .split(',')
+      .map((s) => parseInt(s.trim(), 10))
+      .filter((n) => !isNaN(n));
+  }
+
+  @Get('steuertags')
+  async getSteuertags() {
+    return { ids: await this.getSteuertagIds() };
+  }
+
   @Post('checksum')
   async checksumExists(@Body('checksum') checksum: string) {
     const exists = await this.paperlessService.checksumExists(checksum);
@@ -390,6 +412,19 @@ export class PaperlessController {
 
     oldDocument.tags = oldDocument.tags || [];
 
+    // Im Modal bearbeitbare Inhaltstags übernehmen: Steuertags bleiben
+    // unangetastet, die übrigen (Inhalts-)Tags werden durch die Auswahl ersetzt.
+    if (Array.isArray(body.tags)) {
+      const steuertagIds = new Set(await this.getSteuertagIds());
+      const preserved = oldDocument.tags.filter((t: number) =>
+        steuertagIds.has(t),
+      );
+      const selected = body.tags
+        .map((t: any) => Number(t))
+        .filter((t: number) => !isNaN(t) && !steuertagIds.has(t));
+      oldDocument.tags = Array.from(new Set([...preserved, ...selected]));
+    }
+
     if (isReady) {
       oldDocument.tags = oldDocument.tags.filter((t: number) => t !== 1);
       if (docType?.TagNotReady)

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

@@ -9,6 +9,7 @@ import { DocumentField } from '../database/entities/document-field.entity';
 import { Task } from '../database/entities/task.entity';
 import { Document } from '../database/entities/document.entity';
 import { Attachment } from '../database/entities/attachment.entity';
+import { Setting } from '../database/entities/setting.entity';
 import { PostprocessingModule } from '../postprocessing/postprocessing.module';
 import { AuthModule } from '../auth/auth.module';
 
@@ -20,6 +21,7 @@ import { AuthModule } from '../auth/auth.module';
       Task,
       Document,
       Attachment,
+      Setting,
     ]),
     forwardRef(() => PostprocessingModule),
     AuthModule,

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

@@ -374,6 +374,36 @@ export class SettingsController {
     return this.settingRepo.findOneByOrFail({ ID: parseInt(id, 10) });
   }
 
+  // === Steuertags ===
+  @Get('steuertags')
+  async getSteuertags() {
+    const setting = await this.settingRepo.findOneBy({ Tag: 'steuertag_ids' });
+    const ids = (setting?.Wert ?? '')
+      .split(',')
+      .map((s) => parseInt(s.trim(), 10))
+      .filter((n) => !isNaN(n));
+    return { ids };
+  }
+
+  @Put('steuertags')
+  async updateSteuertags(@Body() body: { ids: number[] }) {
+    const ids = (body.ids ?? [])
+      .map((id) => Number(id))
+      .filter((n) => !isNaN(n));
+    let setting = await this.settingRepo.findOneBy({ Tag: 'steuertag_ids' });
+    if (!setting) {
+      setting = this.settingRepo.create({
+        Typ: 0,
+        Tag: 'steuertag_ids',
+        Wert: ids.join(','),
+      });
+    } else {
+      setting.Wert = ids.join(',');
+    }
+    await this.settingRepo.save(setting);
+    return { ids };
+  }
+
   // === Korrespondenten ===
   @Get('correspondents')
   async getCorrespondents(