feat(10-02): register TendersModule with marketplace self-seed + singleton poll config

- tenders.seed.ts seeds slug 'tender-radar' (isSystem: true, category 'procurement')
- tenders.module.ts self-seeds registry on boot (mirrors DkvModule pattern)
- upserts singleton doe-opendata TenderSourcePollConfig row (global, no forTenant())
- TendersModule added to app.module.ts imports

apps/api/src/app.module.ts

@@ -20,6 +20,7 @@ import { PrismaModule } from './prisma/prisma.module';
 import { SettingsModule } from './settings/settings.module';
 import { TenantGuard } from './tenant/tenant.guard';
 import { TenantModule } from './tenant/tenant.module';
+import { TendersModule } from './tenders/tenders.module';
 import { UserModule } from './user/user.module';
 
 @Module({
@@ -41,6 +42,7 @@ import { UserModule } from './user/user.module';
     SettingsModule,
     DkvModule,
     FavoritesModule,
+    TendersModule,
   ],
   providers: [
     // Global JWT guard: all routes require auth unless @Public()