feat(loki): add single-binary loki and alloy stack

Filesystem storage on local-path-retain, 14d retention. Alloy daemonset ships k8s pod logs to loki-gateway.

loki/k8s/alloy-values.yaml

@@ -0,0 +1,57 @@
+# Pinned chart: grafana/alloy 1.12.1 (app v1.19.2).
+# Install (deferred to deploy task, namespace prometheus):
+#   helm upgrade --install alloy grafana/alloy --version 1.12.1 \
+#     --namespace prometheus --values loki/k8s/alloy-values.yaml --wait
+# DaemonSet ships k8s pod logs (API-tailed, no hostPath mounts) to Loki.
+# Scope phase 1: k8s only, compose leftovers out.
+
+controller:
+  type: daemonset
+  resources:
+    requests:
+      memory: "128Mi"
+      cpu: "50m"
+    limits:
+      memory: "512Mi"
+      cpu: "500m"
+
+image:
+  tag: "v1.19.2"
+
+alloy:
+  configMap:
+    create: true
+    content: |
+      discovery.kubernetes "pods" {
+        role = "pod"
+      }
+
+      discovery.relabel "pods" {
+        targets = discovery.kubernetes.pods.targets
+
+        rule {
+          source_labels = ["__meta_kubernetes_namespace"]
+          target_label  = "namespace"
+        }
+
+        rule {
+          source_labels = ["__meta_kubernetes_pod_name"]
+          target_label  = "pod"
+        }
+
+        rule {
+          source_labels = ["__meta_kubernetes_pod_container_name"]
+          target_label  = "container"
+        }
+      }
+
+      loki.source.kubernetes "pods" {
+        targets    = discovery.relabel.pods.output
+        forward_to = [loki.write.default.receiver]
+      }
+
+      loki.write "default" {
+        endpoint {
+          url = "http://loki-gateway.prometheus.svc.cluster.local/loki/api/v1/push"
+        }
+      }