feat: Complete stub services with real implementations and graceful not-configured responses

- ChangelogService: inject PlatformChangelog repo, query with findAndCount(skip/take), return actual data
- ChangelogModule: add TypeOrmModule.forFeature([PlatformChangelog])
- MapsService: add uploadMap() — SHA-256 checksum, storage path, full entity save
- MapsController: add POST /maps/upload with FileInterceptor, map.manage permission, @UploadedFile
- AuthService: replace console.log stubs with Logger; forgotPassword returns 200 with clear message; resetPassword throws NotImplementedException
- PluginsService: searchUmod returns { results: [], message: 'not yet configured' } instead of bare []
- SteamService: add Logger.warn on every stub path (checkForceWipe, getPlayerSummary)
- SettingsService: add Logger; both Cloudflare DNS stubs emit Logger.warn before DB save
- MigrationService: add Logger; exportConfig logs warning + returns note field; importConfig throws NotImplementedException
- Install @types/multer dev dependency for Express.Multer.File type support

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

backend-nest/src/modules/settings/settings.service.ts

@@ -3,6 +3,7 @@ import {
   NotFoundException,
   BadRequestException,
   ConflictException,
+  Logger,
 } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
@@ -13,6 +14,8 @@ import { UpdateDomainDto } from './dto/update-domain.dto';
 
 @Injectable()
 export class SettingsService {
+  private readonly logger = new Logger(SettingsService.name);
+
   constructor(
     @InjectRepository(PublicSiteConfig)
     private publicSiteConfigRepository: Repository<PublicSiteConfig>,
@@ -97,12 +100,9 @@ export class SettingsService {
         );
       }
 
-      // TODO: Stub Cloudflare DNS provisioning
-      // In production, this would:
-      // 1. Create DNS CNAME record: {subdomain}.corrosionmgmt.com → panel.corrosionmgmt.com
-      // 2. Wait for DNS propagation
-      // 3. Verify SSL certificate provisioning
-      // For now, we just update the database
+      this.logger.warn(
+        `Cloudflare DNS integration not configured — subdomain ${dto.subdomain} updated in DB only`,
+      );
       license.subdomain = dto.subdomain;
     }
 
@@ -115,13 +115,9 @@ export class SettingsService {
           throw new BadRequestException('Invalid custom domain format');
         }
 
-        // TODO: Stub Cloudflare DNS verification
-        // In production, this would:
-        // 1. Instruct user to create CNAME pointing to panel.corrosionmgmt.com
-        // 2. Verify DNS record exists
-        // 3. Provision SSL certificate via Cloudflare
-        // 4. Mark domain as verified
-        // For now, we just update the database
+        this.logger.warn(
+          `Cloudflare DNS integration not configured — custom domain ${dto.custom_domain} updated in DB only`,
+        );
         license.custom_domain = dto.custom_domain;
       } else if (dto.custom_domain === null || dto.custom_domain === '') {
         // Allow clearing custom domain