[ci skip] Move Terraform modules into stack directories

Move all 88 service modules (66 individual + 22 platform) from
modules/kubernetes/<service>/ into their corresponding stack directories:

- Service stacks: stacks/<service>/module/
- Platform stack: stacks/platform/modules/<service>/

This collocates module source code with its Terragrunt definition.
Only shared utility modules remain in modules/kubernetes/:
ingress_factory, setup_tls_secret, dockerhub_secret, oauth-proxy.

All cross-references to shared modules updated to use correct
relative paths. Verified with terragrunt run --all -- plan:
0 adds, 0 destroys across all 68 stacks.

stacks/platform/modules/monitoring/alloy.yaml

@@ -0,0 +1,131 @@
+alloy:
+  configMap:
+    content: |-
+      // Write your Alloy config here:
+      logging {
+        level = "info"
+        format = "logfmt"
+      }
+      loki.write "default" {
+        endpoint {
+          url = "http://loki.monitoring.svc.cluster.local:3100/loki/api/v1/push"
+        }
+      }
+
+      // discovery.kubernetes allows you to find scrape targets from Kubernetes resources.
+      // It watches cluster state and ensures targets are continually synced with what is currently running in your cluster.
+      discovery.kubernetes "pod" {
+        role = "pod"
+      }
+
+      // discovery.relabel rewrites the label set of the input targets by applying one or more relabeling rules.
+      // If no rules are defined, then the input targets are exported as-is.
+      discovery.relabel "pod_logs" {
+        targets = discovery.kubernetes.pod.targets
+
+        // Label creation - "namespace" field from "__meta_kubernetes_namespace"
+        rule {
+          source_labels = ["__meta_kubernetes_namespace"]
+          action = "replace"
+          target_label = "namespace"
+        }
+
+        // Label creation - "pod" field from "__meta_kubernetes_pod_name"
+        rule {
+          source_labels = ["__meta_kubernetes_pod_name"]
+          action = "replace"
+          target_label = "pod"
+        }
+
+        // Label creation - "container" field from "__meta_kubernetes_pod_container_name"
+        rule {
+          source_labels = ["__meta_kubernetes_pod_container_name"]
+          action = "replace"
+          target_label = "container"
+        }
+
+        // Label creation -  "app" field from "__meta_kubernetes_pod_label_app_kubernetes_io_name"
+        rule {
+          source_labels = ["__meta_kubernetes_pod_label_app_kubernetes_io_name"]
+          action = "replace"
+          target_label = "app"
+        }
+
+        // Label creation -  "job" field from "__meta_kubernetes_namespace" and "__meta_kubernetes_pod_container_name"
+        // Concatenate values __meta_kubernetes_namespace/__meta_kubernetes_pod_container_name
+        rule {
+          source_labels = ["__meta_kubernetes_namespace", "__meta_kubernetes_pod_container_name"]
+          action = "replace"
+          target_label = "job"
+          separator = "/"
+          replacement = "$1"
+        }
+
+        // Label creation - "container" field from "__meta_kubernetes_pod_uid" and "__meta_kubernetes_pod_container_name"
+        // Concatenate values __meta_kubernetes_pod_uid/__meta_kubernetes_pod_container_name.log
+        rule {
+          source_labels = ["__meta_kubernetes_pod_uid", "__meta_kubernetes_pod_container_name"]
+          action = "replace"
+          target_label = "__path__"
+          separator = "/"
+          replacement = "/var/log/pods/*$1/*.log"
+        }
+
+        // Label creation -  "container_runtime" field from "__meta_kubernetes_pod_container_id"
+        rule {
+          source_labels = ["__meta_kubernetes_pod_container_id"]
+          action = "replace"
+          target_label = "container_runtime"
+          regex = "^(\\S+):\\/\\/.+$"
+          replacement = "$1"
+        }
+      }
+
+      // loki.source.kubernetes tails logs from Kubernetes containers using the Kubernetes API.
+      loki.source.kubernetes "pod_logs" {
+        targets    = discovery.relabel.pod_logs.output
+        forward_to = [loki.process.pod_logs.receiver]
+      }
+
+      // loki.process receives log entries from other Loki components, applies one or more processing stages,
+      // and forwards the results to the list of receivers in the component's arguments.
+      loki.process "pod_logs" {
+        stage.static_labels {
+            values = {
+              cluster = "default",
+            }
+        }
+
+        forward_to = [loki.write.default.receiver]
+      }
+
+      // Kubernetes audit log collection from /var/log/kubernetes/audit.log
+      // Requires alloy.mounts.varlog=true to mount /var/log from the host
+      local.file_match "audit_logs" {
+        path_targets = [{
+          __path__ = "/var/log/kubernetes/audit.log",
+          job      = "kubernetes-audit",
+          node     = env("HOSTNAME"),
+        }]
+      }
+
+      loki.source.file "audit_logs" {
+        targets    = local.file_match.audit_logs.targets
+        forward_to = [loki.write.default.receiver]
+      }
+
+  # Mount /var/log from the host for file-based log collection (audit logs)
+  mounts:
+    varlog: true
+
+  # Resource limits for DaemonSet pods
+  # Alloy tails logs from all containers on the node via K8s API and batches
+  # them to Loki. Memory scales with number of active log streams (~30-50 per node).
+  # 128Mi was OOMKilled; steady-state usage is ~400-450Mi per pod.
+  resources:
+    requests:
+      cpu: 50m
+      memory: 256Mi
+    limits:
+      cpu: 200m
+      memory: 768Mi