fix: pipeline stop now halts all workers and flushes queues

Workers (ingestion, parser, extractor, aggregation, recommendation,
broker, lake-publisher) now check the pipeline:enabled Redis flag on
each loop iteration and sleep when disabled.

The toggle endpoint flushes all pipeline queues on disable so queued
jobs don't resume when workers eventually check. Broker/trading queues
are excluded from flush to avoid dropping in-flight orders.

services/adapters/broker_service.py

@@ -76,7 +76,7 @@ from services.shared.metrics import (
     RISK_CHECK_FAILURES,
     RISK_EVALUATIONS_TOTAL,
 )
-from services.shared.redis_keys import QUEUE_BROKER, queue_key
+from services.shared.redis_keys import QUEUE_BROKER, is_pipeline_enabled, queue_key
 
 logger = logging.getLogger("broker_service")
 
@@ -923,6 +923,9 @@ async def main() -> None:
 
     try:
         while True:
+            if not await is_pipeline_enabled(rds):
+                await asyncio.sleep(2)
+                continue
             result = await rds.lpop(queue)
             raw = str(result) if result else None
             if raw: