feat(ops): 添加生产监控告警基线

- 新增 Prometheus/Grafana/Loki/Promtail 监控 profile\n- 覆盖 DB、磁盘、慢 API、慢 Prisma、任务失败和小宝摘要 stale 告警\n- 补充 postgres-exporter 自定义查询、Dashboard、部署文档和校验\n\nCo-Authored-By: GPT-5 Codex <codex@openai.com>

deploy/monitoring/grafana/provisioning/datasources/datasources.yml

@@ -0,0 +1,16 @@
+apiVersion: 1
+
+datasources:
+  - name: Prometheus
+    type: prometheus
+    access: proxy
+    url: http://prometheus:9090
+    isDefault: true
+    editable: false
+
+  - name: Loki
+    type: loki
+    access: proxy
+    url: http://loki:3100
+    editable: false
+