[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/blog/module/main.tf

@@ -0,0 +1,130 @@
+variable "tls_secret_name" {}
+variable "tier" { type = string }
+# variable "dockerhub_password" {}
+
+resource "kubernetes_namespace" "website" {
+  metadata {
+    name = "website"
+    labels = {
+      "istio-injection" : "disabled"
+      tier = var.tier
+    }
+  }
+}
+
+module "tls_secret" {
+  source          = "../../../modules/kubernetes/setup_tls_secret"
+  namespace       = kubernetes_namespace.website.metadata[0].name
+  tls_secret_name = var.tls_secret_name
+}
+
+# module "dockerhub_creds" {
+#   source    = "../../../modules/kubernetes/dockerhub_secret"
+#  namespace = kubernetes_namespace.website.metadata[0].name
+#   password  = var.dockerhub_password
+# }
+
+resource "kubernetes_deployment" "blog" {
+  metadata {
+    name      = "blog"
+    namespace = kubernetes_namespace.website.metadata[0].name
+    labels = {
+      run  = "blog"
+      tier = var.tier
+    }
+  }
+  spec {
+    replicas = 3
+    selector {
+      match_labels = {
+        run = "blog"
+      }
+    }
+    template {
+      metadata {
+        labels = {
+          run = "blog"
+        }
+      }
+      spec {
+        container {
+          image = "viktorbarzin/blog:latest"
+          name  = "blog"
+          resources {
+            limits = {
+              cpu    = "0.5"
+              memory = "512Mi"
+            }
+            requests = {
+              cpu    = "250m"
+              memory = "50Mi"
+            }
+          }
+          port {
+            container_port = 80
+          }
+        }
+
+        container {
+          image = "nginx/nginx-prometheus-exporter"
+          name  = "nginx-exporter"
+          args  = ["-nginx.scrape-uri", "http://127.0.0.1:8080/nginx_status"]
+          port {
+            container_port = 9113
+          }
+        }
+      }
+    }
+  }
+}
+
+resource "kubernetes_service" "blog" {
+  metadata {
+    name      = "blog"
+    namespace = kubernetes_namespace.website.metadata[0].name
+    labels = {
+      "run" = "blog"
+    }
+    annotations = {
+      "prometheus.io/scrape" = "true"
+      "prometheus.io/path"   = "/metrics"
+      "prometheus.io/port"   = "9113"
+    }
+  }
+
+  spec {
+    selector = {
+      run = "blog"
+    }
+    port {
+      name        = "http"
+      port        = "80"
+      target_port = "80"
+    }
+    port {
+      name        = "prometheus"
+      port        = "9113"
+      target_port = "9113"
+    }
+  }
+}
+
+module "ingress" {
+  source          = "../../../modules/kubernetes/ingress_factory"
+  namespace       = kubernetes_namespace.website.metadata[0].name
+  name            = "blog"
+  service_name    = "blog"
+  full_host       = "viktorbarzin.me"
+  tls_secret_name = var.tls_secret_name
+  rybbit_site_id  = "da853a2438d0"
+}
+
+module "ingress-www" {
+  source          = "../../../modules/kubernetes/ingress_factory"
+  namespace       = kubernetes_namespace.website.metadata[0].name
+  name            = "blog-www"
+  service_name    = "blog"
+  full_host       = "www.viktorbarzin.me"
+  tls_secret_name = var.tls_secret_name
+  rybbit_site_id  = "da853a2438d0"
+}