[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/authentik/pgbouncer.tf

@@ -0,0 +1,134 @@
+resource "kubernetes_config_map" "pgbouncer_config" {
+  metadata {
+    name      = "pgbouncer-config"
+    namespace = "authentik"
+  }
+
+  data = {
+    "pgbouncer.ini" = templatefile("${path.module}/pgbouncer.ini", { password = var.postgres_password })
+  }
+}
+
+# --- 2️⃣ Secret for user credentials ---
+resource "kubernetes_secret" "pgbouncer_auth" {
+  metadata {
+    name      = "pgbouncer-auth"
+    namespace = "authentik"
+  }
+
+  data = {
+    "userlist.txt" = templatefile("${path.module}/userlist.txt", { password = var.postgres_password })
+  }
+
+  type = "Opaque"
+}
+
+# --- 3️⃣ Deployment ---
+resource "kubernetes_deployment" "pgbouncer" {
+  metadata {
+    name      = "pgbouncer"
+    namespace = "authentik"
+    labels = {
+      app  = "pgbouncer"
+      tier = var.tier
+    }
+  }
+
+  spec {
+    replicas = 3
+
+    selector {
+      match_labels = {
+        app = "pgbouncer"
+      }
+    }
+
+    template {
+      metadata {
+        labels = {
+          app = "pgbouncer"
+        }
+      }
+
+      spec {
+        affinity {
+          pod_anti_affinity {
+            required_during_scheduling_ignored_during_execution {
+              label_selector {
+                match_expressions {
+                  key      = "component"
+                  operator = "In"
+                  values   = ["server"]
+                }
+              }
+              topology_key = "kubernetes.io/hostname"
+            }
+          }
+        }
+        container {
+          name              = "pgbouncer"
+          image             = "edoburu/pgbouncer:latest"
+          image_pull_policy = "IfNotPresent"
+
+          port {
+            container_port = 6432
+          }
+
+          volume_mount {
+            name       = "config"
+            mount_path = "/etc/pgbouncer/pgbouncer.ini"
+            sub_path   = "pgbouncer.ini"
+          }
+
+          volume_mount {
+            name       = "auth"
+            mount_path = "/etc/pgbouncer/userlist.txt"
+            sub_path   = "userlist.txt"
+          }
+
+          env {
+            name  = "DATABASES_AUTHENTIK"
+            value = "host=postgres port=5432 dbname=authentik user=authentik password=${var.postgres_password}"
+          }
+        }
+
+        volume {
+          name = "config"
+          config_map {
+            name = kubernetes_config_map.pgbouncer_config.metadata[0].name
+          }
+        }
+
+        volume {
+          name = "auth"
+          secret {
+            secret_name = kubernetes_secret.pgbouncer_auth.metadata[0].name
+          }
+        }
+      }
+    }
+  }
+  depends_on = [kubernetes_secret.pgbouncer_auth]
+}
+
+# --- 4️⃣ Service ---
+resource "kubernetes_service" "pgbouncer" {
+  metadata {
+    name      = "pgbouncer"
+    namespace = "authentik"
+  }
+
+  spec {
+    selector = {
+      app = "pgbouncer"
+    }
+
+    port {
+      port        = 6432
+      target_port = 6432
+      protocol    = "TCP"
+    }
+
+    type = "ClusterIP"
+  }
+}