[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/send/module/main.tf

@@ -0,0 +1,119 @@
+variable "tls_secret_name" {}
+variable "tier" { type = string }
+
+resource "kubernetes_namespace" "send" {
+  metadata {
+    name = "send"
+    labels = {
+      "istio-injection" : "disabled"
+      tier = var.tier
+    }
+  }
+}
+
+module "tls_secret" {
+  source          = "../../../modules/kubernetes/setup_tls_secret"
+  namespace       = kubernetes_namespace.send.metadata[0].name
+  tls_secret_name = var.tls_secret_name
+}
+
+resource "kubernetes_deployment" "send" {
+  metadata {
+    name      = "send"
+    namespace = kubernetes_namespace.send.metadata[0].name
+    labels = {
+      app  = "send"
+      tier = var.tier
+    }
+    annotations = {
+      "reloader.stakater.com/search" = "true"
+    }
+  }
+  spec {
+    replicas = 1
+    selector {
+      match_labels = {
+        app = "send"
+      }
+    }
+    template {
+      metadata {
+        labels = {
+          app = "send"
+        }
+      }
+      spec {
+        container {
+          image = "registry.gitlab.com/timvisee/send:latest"
+          name  = "send"
+
+          port {
+            container_port = 1443
+          }
+          env {
+            name  = "FILE_DIR"
+            value = "/uploads"
+          }
+          env {
+            name  = "BASE_URL"
+            value = "https://send.viktorbarzin.me"
+          }
+          env {
+            name  = "MAX_FILE_SIZE"
+            value = "5368709120"
+          }
+          env {
+            name  = "MAX_DOWNLOADS"
+            value = 10 # try to minimize abusive behaviour
+          }
+          env {
+            name  = "MAX_EXPIRE_SECONDS"
+            value = 7 * 24 * 3600
+          }
+          env {
+            name  = "REDIS_HOST"
+            value = "redis.redis.svc.cluster.local"
+          }
+          volume_mount {
+            name       = "data"
+            mount_path = "/uploads"
+          }
+        }
+        volume {
+          name = "data"
+          nfs {
+            path   = "/mnt/main/send"
+            server = "10.0.10.15"
+          }
+        }
+      }
+    }
+  }
+}
+resource "kubernetes_service" "send" {
+  metadata {
+    name      = "send"
+    namespace = kubernetes_namespace.send.metadata[0].name
+    labels = {
+      app = "send"
+    }
+  }
+
+  spec {
+    selector = {
+      app = "send"
+    }
+    port {
+      name = "http"
+      port = 1443
+    }
+  }
+}
+module "ingress" {
+  source          = "../../../modules/kubernetes/ingress_factory"
+  namespace       = kubernetes_namespace.send.metadata[0].name
+  name            = "send"
+  tls_secret_name = var.tls_secret_name
+  port            = 1443
+  rybbit_site_id  = "c1b8f8aa831b"
+}