Mejoras de sesion: estabilizacion, IA, Nexus Yonke y marketplace B2B

- F0 blindaje: Redis/Celery, pg_hba sin trust LAN, secretos a env 600, backups, webhook auth, jobs muertos
- F1 caja: bugs POS, reembolsos al corte, apartados, CFDI, topes de descuento en cotizacion/apartado
- F2/F7 IA de catalogo: autocategorizacion, dedup de SKUs con embeddings, OCR de facturas, descripciones, claves SAT, limpieza de fitment
- F3 IA en el flujo: vision Yonke, preguntas MeLi, venta cruzada, anomalias, sinonimos, busqueda semantica (rerank/embeddings)
- F4/F8 escala y cartera: /metrics+Prometheus+Grafana, pool, score de credito, churn, metricas multi-tenant
- Nexus Yonke (M1-M6): modelo de datos 1-de-1, alta por donador, vitrina publica, MeLi usado, consignacion, garantia por dias, reportes, etiquetas
- Marketplace B2B entre yonkes (catalogo + pedidos cross-tenant)
- Seguridad: auth en /api/admin/* (35 endpoints), alertas por tenant
- Migraciones v4.27/v4.28; timers expire-demos y rollup-metrics

docker/grafana/provisioning/dashboards/nexus-gunicorn.json

@@ -1,7 +1,7 @@
 {
   "uid": "nexus-app",
   "title": "Nexus — Application",
-  "tags": ["gunicorn", "flask"],
+  "tags": ["app", "flask", "nexus"],
   "timezone": "browser",
   "schemaVersion": 36,
   "refresh": "30s",
@@ -26,15 +26,15 @@
   "panels": [
     {
       "id": 1,
-      "title": "Request Rate (nginx)",
+      "title": "Request Rate (by app / status)",
       "type": "timeseries",
       "gridPos": {"h": 8, "w": 12, "x": 0, "y": 0},
       "datasource": {"type": "prometheus", "uid": "${datasource}"},
       "targets": [
         {
           "datasource": {"type": "prometheus", "uid": "${datasource}"},
-          "expr": "rate(nginx_http_requests_total[5m])",
-          "legendFormat": "Requests/sec",
+          "expr": "sum by (app, status) (rate(nexus_http_requests_total[5m]))",
+          "legendFormat": "{{app}} {{status}}",
           "refId": "A"
         }
       ],
@@ -49,20 +49,20 @@
     },
     {
       "id": 2,
-      "title": "Response Time (nginx)",
+      "title": "Response Time p95 / p99",
       "type": "timeseries",
       "gridPos": {"h": 8, "w": 12, "x": 12, "y": 0},
       "datasource": {"type": "prometheus", "uid": "${datasource}"},
       "targets": [
         {
           "datasource": {"type": "prometheus", "uid": "${datasource}"},
-          "expr": "histogram_quantile(0.95, sum(rate(nginx_http_request_duration_seconds_bucket[5m])) by (le))",
+          "expr": "histogram_quantile(0.95, sum by (le) (rate(nexus_http_request_duration_seconds_bucket[5m])))",
           "legendFormat": "p95",
           "refId": "A"
         },
         {
           "datasource": {"type": "prometheus", "uid": "${datasource}"},
-          "expr": "histogram_quantile(0.99, sum(rate(nginx_http_request_duration_seconds_bucket[5m])) by (le))",
+          "expr": "histogram_quantile(0.99, sum by (le) (rate(nexus_http_request_duration_seconds_bucket[5m])))",
           "legendFormat": "p99",
           "refId": "B"
         }
@@ -78,15 +78,15 @@
     },
     {
       "id": 3,
-      "title": "Active Workers",
+      "title": "In-flight Requests",
       "type": "timeseries",
       "gridPos": {"h": 8, "w": 12, "x": 0, "y": 8},
       "datasource": {"type": "prometheus", "uid": "${datasource}"},
       "targets": [
         {
           "datasource": {"type": "prometheus", "uid": "${datasource}"},
-          "expr": "count by (instance) (node_processes_state{state=\"S\", cmdline=~\".*gunicorn.*\"})",
-          "legendFormat": "Workers {{instance}}",
+          "expr": "sum by (app) (nexus_http_requests_in_flight)",
+          "legendFormat": "{{app}}",
           "refId": "A"
         }
       ],
@@ -108,8 +108,8 @@
       "targets": [
         {
           "datasource": {"type": "prometheus", "uid": "${datasource}"},
-          "expr": "rate(nginx_http_requests_total{status=~\"5..\"}[5m])",
-          "legendFormat": "5xx/sec",
+          "expr": "sum by (app) (rate(nexus_http_requests_total{status=\"5xx\"}[5m]))",
+          "legendFormat": "{{app}} 5xx/s",
           "refId": "A"
         }
       ],
@@ -124,22 +124,22 @@
     },
     {
       "id": 5,
-      "title": "Memory per Worker",
+      "title": "Master DB Connections",
       "type": "timeseries",
       "gridPos": {"h": 8, "w": 24, "x": 0, "y": 16},
       "datasource": {"type": "prometheus", "uid": "${datasource}"},
       "targets": [
         {
           "datasource": {"type": "prometheus", "uid": "${datasource}"},
-          "expr": "process_resident_memory_bytes{cmdline=~\".*gunicorn.*\"} / 1024 / 1024",
-          "legendFormat": "{{cmdline}}",
+          "expr": "nexus_db_connections",
+          "legendFormat": "{{app}} ({{database}})",
           "refId": "A"
         }
       ],
       "fieldConfig": {
         "defaults": {
           "custom": {"drawStyle": "line", "lineWidth": 2, "fillOpacity": 10},
-          "unit": "mbytes",
+          "unit": "short",
           "min": 0
         },
         "overrides": []