feat(domaincheck): support all TLDs with suggestion alternatives

- Accept full domains (e.g. "example.xyz") not just labels
- Check the entered TLD as primary result
- Show .de, .com, .net, .org as alternative suggestions below
- Primary result highlighted with accent border
- Input without TLD still works (shows all 4 suggestions)
- Updated i18n placeholders and added "suggestions" label

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

apps/api/src/domaincheck/domaincheck.controller.ts

@@ -3,32 +3,14 @@ import { UseModule } from '../module-registry/module.guard';
 import { CheckDomainDto } from './dto/check-domain.dto';
 import { DomaincheckService } from './domaincheck.service';
 
-/**
- * Controller for the Domaincheck module.
- *
- * POST /modules/domaincheck/check — accepts a domain label, checks TLD
- * variants via DNS, and returns availability status for each.
- *
- * Protected by @UseModule('domaincheck') which ensures the requesting
- * tenant has the domaincheck module activated (per T-03-08).
- */
 @Controller('modules/domaincheck')
 @UseModule('domaincheck')
 export class DomaincheckController {
   constructor(private readonly domaincheckService: DomaincheckService) {}
 
-  /**
-   * Check domain availability across TLD variants.
-   *
-   * @param dto - Contains domain label and optional TLD list
-   * @returns Domain and results array with tld, fqdn, and status
-   */
   @Post('check')
   async checkDomain(@Body() dto: CheckDomainDto) {
-    const results = await this.domaincheckService.checkDomain(
-      dto.domain,
-      dto.tlds,
-    );
+    const results = await this.domaincheckService.checkDomain(dto.domain);
 
     return {
       domain: dto.domain,