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/changelog/changelog.module.ts

@@ -1,8 +1,11 @@
 import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
 import { ChangelogController } from './changelog.controller';
 import { ChangelogService } from './changelog.service';
+import { PlatformChangelog } from '../../entities/platform-changelog.entity';
 
 @Module({
+  imports: [TypeOrmModule.forFeature([PlatformChangelog])],
   controllers: [ChangelogController],
   providers: [ChangelogService],
 })