fix(gateway): add missing @Inject() decorators causing silent startup hang

tsx/esbuild doesn't support emitDecoratorMetadata, so NestJS can't
infer constructor parameter types at runtime. Three services were
missing explicit @Inject() decorators:

- SummarizationService: EmbeddingService parameter
- CronService: SummarizationService parameter
- SkillsController: SkillsService parameter

Without these, NestJS DI hangs forever during onModuleInit resolution
with no error output — the process silently exits (or hangs with a
keepAlive).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/gateway/src/log/cron.service.ts

@@ -1,4 +1,10 @@
-import { Injectable, Logger, type OnModuleInit, type OnModuleDestroy } from '@nestjs/common';
+import {
+  Inject,
+  Injectable,
+  Logger,
+  type OnModuleInit,
+  type OnModuleDestroy,
+} from '@nestjs/common';
 import cron from 'node-cron';
 import { SummarizationService } from './summarization.service.js';
 
@@ -7,7 +13,7 @@ export class CronService implements OnModuleInit, OnModuleDestroy {
   private readonly logger = new Logger(CronService.name);
   private readonly tasks: cron.ScheduledTask[] = [];
 
-  constructor(private readonly summarization: SummarizationService) {}
+  constructor(@Inject(SummarizationService) private readonly summarization: SummarizationService) {}
 
   onModuleInit(): void {
     const summarizationSchedule = process.env['SUMMARIZATION_CRON'] ?? '0 */6 * * *'; // every 6 hours

apps/gateway/src/log/summarization.service.ts

@@ -29,7 +29,7 @@ export class SummarizationService {
   constructor(
     @Inject(LOG_SERVICE) private readonly logService: LogService,
     @Inject(MEMORY) private readonly memory: Memory,
-    private readonly embeddings: EmbeddingService,
+    @Inject(EmbeddingService) private readonly embeddings: EmbeddingService,
     @Inject(DB) private readonly db: Db,
   ) {
     this.apiKey = process.env['OPENAI_API_KEY'];