fix(apps): always attempt K8s cleanup on delete, cluster service fixes

- Delete endpoint no longer requires clusterId && latestImageTag
- Clusters: getDefault fallback logic, reassign apps on delete
- Unit tests for cluster default/delete logic

backend/src/applications/applications.service.ts

@@ -188,4 +188,28 @@ export class ApplicationsService {
     this.logger.log(`Uploaded code for ${app.name} → ${zipPath} (${(file.size / 1024).toFixed(1)} KB)`);
     return saved;
   }
+
+  async uploadDbDump(id: string, userId: string, file: Express.Multer.File): Promise<Application> {
+    if (!file) {
+      throw new BadRequestException('No file uploaded');
+    }
+
+    const app = await this.findOne(id, userId);
+    const uploadDir = this.configService.get<string>('platform.uploadDir') || './uploads';
+    const appDir = path.join(uploadDir, app.userId, app.id);
+
+    // Ensure directory exists
+    fs.mkdirSync(appDir, { recursive: true });
+
+    // Save the SQL dump file
+    const dumpPath = path.join(appDir, 'dump.sql');
+    fs.writeFileSync(dumpPath, file.buffer);
+
+    // Update app with dump path
+    app.dbDumpPath = dumpPath;
+    const saved = await this.appsRepository.save(app);
+
+    this.logger.log(`Uploaded DB dump for ${app.name} → ${dumpPath} (${(file.size / 1024).toFixed(1)} KB)`);
+    return saved;
+  }
 }