scaffold: hub-and-spoke layout, 4-network topology, 13 stack stubs

Initial structure for R&D infrastructure:

- stacks/ — 13 reusable, runnable stack stubs (kebab-case)
  cloud-and-edge: node-red, influxdb, grafana, keycloak, portainer,
                  nginx-proxy, mqtt, postfix
  cloud-only:     wireguard-server, gitea, jenkins, sql (postgres stub)
  edge-only:      wireguard-client

- cloud/ — single central hub composition with 4 networks
           (edge, app, data internal, mgmt) and include: stubs
- sites/ — per-plant edge folders (template README only for now)
- docs/architecture.md — hub-and-spoke + ingress + segmentation rationale

Network model: only nginx-proxy (80/443/8883) and wireguard-server
(51820/udp) publish ports on the cloud host. Edge nginx publishes
80/443 on plant-LAN interface only. MQTT cloud-side via nginx stream
proxy; MQTT edge-side internal-only; Postfix outbound-only.

OT layer (OPCUA, PLCs) is out of scope for this repo.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

stacks/gitea/.env.example

@@ -0,0 +1,6 @@
+GITEA_ROOT_URL=
+GITEA_DB_TYPE=postgres
+GITEA_DB_HOST=sql:5432
+GITEA_DB_NAME=gitea
+GITEA_DB_USER=gitea
+GITEA_DB_PASSWORD=

stacks/gitea/README.md

@@ -0,0 +1,7 @@
+# gitea
+
+Self-hosted git server. **Cloud-only stack.** (External repos live at `gitea.wbd-rd.nl`; this is for R&D internal use.)
+
+- **Networks**: `app` (UI) + `data` (DB backend in `sql` stack)
+- **Volume**: `gitea-data` (repos + LFS + actions runners)
+- **TODO**: SSH access strategy (nginx stream proxy port 22, or skip and use HTTPS-only), Keycloak OIDC, runners for Gitea Actions

stacks/gitea/compose.yml

@@ -0,0 +1,28 @@
+# gitea — git server (cloud only)
+# Networks: app + data (uses sql stack as DB backend)
+
+services:
+  gitea:
+    image: gitea/gitea:1.22
+    restart: unless-stopped
+    networks: [app, data]
+    environment:
+      USER_UID: "1000"
+      USER_GID: "1000"
+      GITEA__server__ROOT_URL: ${GITEA_ROOT_URL}
+      GITEA__database__DB_TYPE: ${GITEA_DB_TYPE:-postgres}
+      GITEA__database__HOST: ${GITEA_DB_HOST:-sql:5432}
+      GITEA__database__NAME: ${GITEA_DB_NAME:-gitea}
+      GITEA__database__USER: ${GITEA_DB_USER}
+      GITEA__database__PASSWD: ${GITEA_DB_PASSWORD}
+      TZ: ${TZ:-Europe/Amsterdam}
+    volumes:
+      - gitea-data:/data
+    # SSH port: TODO — decide if Gitea SSH (22/2222) is exposed via nginx stream or skipped
+
+networks:
+  app:
+  data:
+
+volumes:
+  gitea-data: