Revert "feat: migrate frontend to Astro + expand AI moderation + backend admin/runtime config"

This reverts commit d59b59a7a7.

services/discord-gateway/src/modules/ai-moderation/circuitBreaker.ts

@@ -36,10 +36,6 @@ export const workerPool = new Piscina({
   filename: fileURLToPath(getAnalysisWorkerUrl()),
   execArgv: process.execArgv,
   maxThreads: config.PISCINA_MAX_THREADS ?? availableParallelism(),
-  // Each worker processes at most 1 task at a time so the pool itself
-  // acts as the concurrency governor. Combined with per-worker p-limit
-  // inside concurrencyLimiter.ts, this prevents LLM API overload.
-  concurrentTasksPerWorker: 1,
 });
 
 /**
@@ -232,7 +228,7 @@ export function scheduleAutoDelete(row: MessageRecord): void {
   };
 
   if (config.AUTO_DELETE_FLAGGED_DELAY_MS > 0) {
-    setTimeout(run, config.AUTO_DELETE_FLAGGED_DELAY_MS).unref();
+    setTimeout(run, config.AUTO_DELETE_FLAGGED_DELAY_MS);
     return;
   }
   setImmediate(run);