fix(schedule): register ScheduleModule.forRoot() exactly once

src/app.module.ts

@@ -72,6 +72,7 @@ import { UserAtprotoIdentityModule } from './user-atproto-identity/user-atproto-
 import { AtprotoIdentityModule } from './atproto-identity/atproto-identity.module';
 import { MeModule } from './me/me.module';
 import { DIDApiModule } from './did-api/did-api.module';
+import { ScheduleModule } from '@nestjs/schedule';
 
 const infrastructureDatabaseModule = TypeOrmModule.forRootAsync({
   useClass: TypeOrmConfigService,
@@ -123,6 +124,15 @@ const infrastructureDatabaseModule = TypeOrmModule.forRootAsync({
       inject: [ConfigService],
     }),
     EventEmitterModule.forRoot(),
+    // The ONLY ScheduleModule registration in the application. forRoot() sets
+    // global: true and its ScheduleExplorer scans every provider in the
+    // container, so feature modules import nothing and their @Cron methods are
+    // still discovered. Two rules follow: calling forRoot() in more than one
+    // module creates one ScheduleExplorer per call site and fires every cron
+    // once per call site; and importing the BARE ScheduleModule creates a
+    // second module whose SchedulerOrchestrator cannot resolve
+    // SchedulerRegistry (only forRoot() provides it), which fails bootstrap.
+    ScheduleModule.forRoot(),
     ThrottlerModule.forRoot([
       {
         ttl: 60000, // 60 seconds

src/atproto-publisher/atproto-publisher.module.ts

@@ -1,5 +1,4 @@
 import { Module, forwardRef } from '@nestjs/common';
-import { ScheduleModule } from '@nestjs/schedule';
 import { AtprotoPublisherService } from './atproto-publisher.service';
 import { AtprotoSyncScheduler } from './atproto-sync-scheduler';
 import { PdsModule } from '../pds/pds.module';
@@ -31,7 +30,8 @@ import { TenantModule } from '../tenant/tenant.module';
  */
 @Module({
   imports: [
-    ScheduleModule.forRoot(),
+    // @Cron methods are discovered by the single global
+    // ScheduleModule.forRoot() in AppModule; no import is needed here.
     PdsModule,
     forwardRef(() => BlueskyModule),
     AtprotoIdentityModule,

src/database/database-metrics.module.ts

@@ -1,5 +1,4 @@
 import { Module } from '@nestjs/common';
-import { ScheduleModule } from '@nestjs/schedule';
 import { DatabaseMetricsService } from './database-metrics.service';
 import {
   makeGaugeProvider,
@@ -57,7 +56,6 @@ const databaseMetricsProviders = [
 ];
 
 @Module({
-  imports: [ScheduleModule],
   providers: [DatabaseMetricsService, ...databaseMetricsProviders],
   exports: [DatabaseMetricsService, ...databaseMetricsProviders],
 })

src/external-calendar/external-calendar.module.ts

@@ -1,5 +1,4 @@
 import { Module } from '@nestjs/common';
-import { ScheduleModule } from '@nestjs/schedule';
 import { ExternalCalendarService } from './external-calendar.service';
 import { ExternalCalendarController } from './external-calendar.controller';
 import { AvailabilityController } from './availability.controller';
@@ -10,7 +9,9 @@ import { CalendarSourceModule } from '../calendar-source/calendar-source.module'
 import { TenantModule } from '../tenant/tenant.module';
 
 @Module({
-  imports: [ScheduleModule.forRoot(), TenantModule, CalendarSourceModule],
+  // @Cron methods are discovered by the single global
+  // ScheduleModule.forRoot() in AppModule; no import is needed here.
+  imports: [TenantModule, CalendarSourceModule],
   controllers: [ExternalCalendarController, AvailabilityController],
   providers: [
     ExternalCalendarService,

src/matrix/matrix.module.ts

@@ -1,6 +1,5 @@
 import { Module, forwardRef } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
-import { ScheduleModule } from '@nestjs/schedule';
 import { TerminusModule } from '@nestjs/terminus';
 import { MatrixController } from './matrix.controller';
 import { MatrixAppServiceController } from './controllers/matrix-appservice.controller';
@@ -37,7 +36,6 @@ configureMatrixLogging();
   imports: [
     ConfigModule.forFeature(matrixConfig),
     TerminusModule,
-    ScheduleModule.forRoot(),
     forwardRef(() => UserModule),
     TenantModule,
     forwardRef(() => AuthModule),

src/metrics/metrics.module.ts

@@ -1,6 +1,5 @@
 import { Module, OnModuleInit } from '@nestjs/common';
 import { MetricsService } from './metrics.service';
-import { ScheduleModule } from '@nestjs/schedule';
 import {
   PrometheusModule,
   makeGaugeProvider,
@@ -149,7 +148,8 @@ const atprotoHandleMetrics = [
 
 @Module({
   imports: [
-    ScheduleModule.forRoot(),
+    // @Cron methods are discovered by the single global
+    // ScheduleModule.forRoot() in AppModule; no import is needed here.
     PrometheusModule.register({
       defaultMetrics: {
         enabled: true,