Add local Docker deployment and submodules

- docker-compose.yml: builder, nginx web server and a LaTeX container (profile "latex")
  for regenerating the SVG drawings
- Makefile, scripts/fetch.sh, .env.example
- 50ohm, 50ohm-contents-dl and 50ohm-ansible as submodules tracking branch sv

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

docker-compose.yml

@@ -0,0 +1,53 @@
+# Local deploy of the Swedish 50ohm site.
+#
+#   make build     generate the static site  (./50ohm + ./50ohm-contents-dl  ->  ./site-build)
+#   make up        serve it on http://127.0.0.1:8080
+#   make drawings  regenerate stale SVG drawings from their .tex sources (profile "latex")
+#
+# The repos are bind-mounted, never copied: nothing the containers do ends up in git except
+# regenerated drawings/*.svg in the content repo (which you do want to commit).
+# Containers run as your user (HOST_UID/HOST_GID) so no root-owned files appear in the repos.
+
+x-user: &user "${HOST_UID:-1000}:${HOST_GID:-1000}"
+
+services:
+  build:
+    build:
+      context: ./docker/builder
+      additional_contexts:
+        src: ./50ohm
+    image: 50ohm-se-builder
+    user: *user
+    volumes:
+      - ./50ohm:/app:ro
+      - ./50ohm-contents-dl:/content:ro
+      - ./site-build:/out
+    profiles: ["build"]
+
+  web:
+    image: nginx:1.27-alpine
+    ports:
+      - "${BIND_ADDR:-127.0.0.1}:${WEB_PORT:-8080}:80"
+    volumes:
+      - ./site-build:/usr/share/nginx/html:ro
+      - ./docker/web/default.conf:/etc/nginx/conf.d/default.conf:ro
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "wget", "-q", "--spider", "http://127.0.0.1/index.html"]
+      interval: 30s
+      timeout: 3s
+      retries: 3
+
+  latex:
+    build:
+      context: ./docker/latex
+    image: 50ohm-se-latex
+    user: *user
+    working_dir: /content
+    volumes:
+      - ./50ohm-contents-dl:/content
+      - texcache:/cache
+    profiles: ["latex"]
+
+volumes:
+  texcache: