feat: pipeline on/off toggle with per-stage Helm control

- Added pipelineEnabled flag to Helm values (default: true)
- Worker services (scheduler, ingestion, parser, extractor, aggregation,
  recommendation, broker-adapter, lake-publisher) scale to 0 when disabled
- API services always run regardless of toggle
- Redis-based runtime toggle: POST /api/ops/pipeline/toggle
- Scheduler checks the flag before each cycle
- Frontend: green/red Pipeline ON/OFF button on the pipeline page
- Beta defaults to pipelineEnabled: false
- Base values.yaml: blanked external URLs (Ollama, Polygon, Alpaca)
  so stages only connect to what they explicitly configure

services/api/app.py

@@ -41,7 +41,7 @@ from services.shared.audit import get_entity_audit_trail, get_order_audit_trail,
 from services.shared.config import load_config
 from services.shared.db import get_pg_pool, get_redis
 from services.shared.logging import new_trace_id, set_trace_context, setup_logging
-from services.shared.redis_keys import QUEUE_PREFIX, queue_key
+from services.shared.redis_keys import PREFIX, QUEUE_PREFIX, queue_key
 from services.shared.schemas import MAJOR_DECISION_CATALYSTS
 
 logger = logging.getLogger("query_api")
@@ -1787,8 +1787,13 @@ async def get_pipeline_health(
             except Exception:
                 pass
 
+    # Pipeline enabled flag
+    pipeline_flag = await rds.get(_PIPELINE_ENABLED_KEY) if rds else None
+    pipeline_enabled = pipeline_flag != "0" if pipeline_flag is not None else True
+
     return {
         "hours": hours,
+        "pipeline_enabled": pipeline_enabled,
         "document_stages": [_row_to_dict(r) for r in doc_stages],
         "parsing": _row_to_dict(parse_quality) if parse_quality else {},
         "extraction": _row_to_dict(extraction_stats) if extraction_stats else {},
@@ -1927,6 +1932,34 @@ async def retry_failed_extractions_endpoint():
     return {"retried": len(doc_ids), "message": f"Re-enqueued {len(doc_ids)} documents for extraction"}
 
 
+# ---------------------------------------------------------------------------
+# Pipeline On/Off Toggle
+# ---------------------------------------------------------------------------
+
+_PIPELINE_ENABLED_KEY = f"{PREFIX}:pipeline:enabled"
+
+
+@app.get("/api/ops/pipeline/toggle")
+async def get_pipeline_toggle():
+    """Get the current pipeline enabled/disabled state."""
+    val = await rds.get(_PIPELINE_ENABLED_KEY)
+    # Default to enabled if key doesn't exist
+    enabled = val != "0"
+    return {"pipeline_enabled": enabled}
+
+
+@app.post("/api/ops/pipeline/toggle")
+async def set_pipeline_toggle(body: dict[str, Any]):
+    """Toggle the pipeline on or off.
+
+    Accepts: { "enabled": true/false }
+    Workers check this flag before processing jobs.
+    """
+    enabled = body.get("enabled", True)
+    await rds.set(_PIPELINE_ENABLED_KEY, "1" if enabled else "0")
+    return {"pipeline_enabled": enabled, "message": f"Pipeline {'enabled' if enabled else 'disabled'}"}
+
+
 @app.get("/api/ops/sources/coverage-gaps")
 async def get_source_coverage_gaps():
     """Identify symbols with missing or insufficient source coverage.