Update kube-prometheus-stack values.yaml to clarify Loki datasource configuration and enhance observability documentation in CLUSTER-BUILD.md. Include deployment instructions for Loki and Fluent Bit, and mark tasks related to Grafana integration as completed.

clusters/noble/apps/fluent-bit/namespace.yaml

@@ -0,0 +1,10 @@
+# Fluent Bit (tail container logs → Loki) — apply before Helm.
+# HostPath mounts under /var/log require PSA privileged (same idea as monitoring/node-exporter).
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: logging
+  labels:
+    pod-security.kubernetes.io/enforce: privileged
+    pod-security.kubernetes.io/audit: privileged
+    pod-security.kubernetes.io/warn: privileged