feat(deploy): Caddy reverse proxy — clean port-80 URL, server internal

Operators/admins reach the booth at http://<name-or-ip>/ (no :3000). Adds a caddy:2-alpine
proxy to the prod override that reverse-proxies :80 → server:3000 (the /api/ws WebSocket
upgrades pass through natively); the server is now `expose: 3000` (internal, no published
port), vision stays internal. The Caddyfile binds `:80` so it matches ANY hostname/IP —
works for the booth IP, localhost, AND parksystems.msai.al (pointed at the booth via
hosts/DNS on-site; no domain baked into any image). TLS later = swap `:80` for the real
hostname + uncomment :443 → Caddy auto-provisions HTTPS.

Pairs with the relative-/api SPA fix (77b2acb): together verified end-to-end locally —
through Caddy on :80 with Host: parksystems.msai.al, GET / serves the SPA, assets/health
200, and POST /api/auth/login reaches the server (real 401, no CORS/connection error).

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

docker-compose.prod.yml

@@ -1,14 +1,41 @@
 # PROD override: pull pinned registry images (no local build), restart always, real
-# recognizer, and keep vision INTERNAL (only the server port is published). Use with the
-# base file and pin TAG to the branch/SHA you deploy:
+# recognizer, and a CADDY reverse proxy in front so operators reach the booth on a clean
+# port-80 URL (no :3000) — and a path to real TLS later. Server + vision stay INTERNAL
+# (only Caddy publishes a port). Use with the base file and pin TAG to the branch you deploy:
 #   REGISTRY=git.infra.msai.al/mca/parking_solution TAG=main \
 #     docker compose -f docker-compose.yml -f docker-compose.prod.yml up -d
+# See wiki/decisions/container-deployment.md.
 
 services:
-  server:
+  # Reverse proxy: :80 → server:3000 (WebSocket /api/ws upgrades pass through natively).
+  # Caddy is a single static binary with a one-line proxy config; swapping http:// for the
+  # site's real hostname later enables automatic HTTPS. The booth is reached at
+  # http://<name-or-ip>/ (the name set via hosts/DNS on-site — NOT baked into any image).
+  proxy:
+    image: caddy:2-alpine
     restart: always
     ports:
-      - "3000:3000"
+      - "80:80"
+      # - "443:443"   # uncomment when moving to TLS (and set a real hostname in Caddyfile)
+    volumes:
+      - ./Caddyfile:/etc/caddy/Caddyfile:ro
+      - caddy-data:/data
+      - caddy-config:/config
+    depends_on:
+      - server
+    networks:
+      - parking
+    logging:
+      driver: json-file
+      options:
+        max-size: "10m"
+        max-file: "3"
+
+  server:
+    restart: always
+    # No published port — only the proxy reaches the server, over the private network.
+    expose:
+      - "3000"
     logging:
       driver: json-file
       options:
@@ -26,3 +53,7 @@ services:
       options:
         max-size: "10m"
         max-file: "3"
+
+volumes:
+  caddy-data:
+  caddy-config: