Deployment Redesign

Implemented the deployment redesign.
- Added Dockge-first-class stacks:
  - [stacks/infra/compose.yaml]
  - [stacks/caddy/compose.yaml]
- Added reusable business template: [deploy/business-compose.yaml.template]
- Added automated provisioning: [scripts/create-business.sh]
- Added per-business database/user, secrets, media volume, private networks, and Caddy route generation.
- Removed Traefik and manual business Compose files.
- Updated environment templates, .gitignore, and deployment documentation in [README.md]
Validation completed:
- Docker Compose config passed for infra, Caddy, and generated business stacks.
- Shell syntax validation passed.
- Registry image tags containing / were tested.
- No remaining Traefik or obsolete deployment references found.

stacks/caddy/Caddyfile

@@ -0,0 +1,5 @@
+{
+    email {$ACME_EMAIL}
+}
+
+import /etc/caddy/sites/*.caddy

stacks/caddy/compose.yaml

@@ -0,0 +1,30 @@
+name: nextchair-caddy
+
+services:
+  nextchair-caddy:
+    image: caddy:2.10-alpine
+    container_name: nextchair-caddy
+    restart: unless-stopped
+    env_file:
+      - .env
+    ports:
+      - "80:80"
+      - "443:443"
+    volumes:
+      - ./Caddyfile:/etc/caddy/Caddyfile:ro
+      - ./sites:/etc/caddy/sites:ro
+      - nextchair-caddy-data:/data
+      - nextchair-caddy-config:/config
+    networks:
+      - nextchair-proxy
+
+volumes:
+  nextchair-caddy-data:
+    name: nextchair-caddy-data
+  nextchair-caddy-config:
+    name: nextchair-caddy-config
+
+networks:
+  nextchair-proxy:
+    name: nextchair-proxy
+    external: true

stacks/infra/compose.yaml

@@ -0,0 +1,31 @@
+name: nextchair-infra
+
+services:
+  nextchair-mysql:
+    image: mysql:8.0
+    container_name: nextchair-mysql
+    restart: unless-stopped
+    env_file:
+      - ../../.env.infra
+    command: --character-set-server=utf8mb4 --collation-server=utf8mb4_0900_ai_ci
+    ports:
+      - "${MYSQL_HOST_PORT:-127.0.0.1:3306}:3306"
+    volumes:
+      - nextchair-mysql-data:/var/lib/mysql
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "127.0.0.1", "-u", "root", "-p${MYSQL_ROOT_PASSWORD:-change-me-too}"]
+      interval: 5s
+      timeout: 5s
+      retries: 20
+      start_period: 10s
+    networks:
+      - nextchair-db
+
+volumes:
+  nextchair-mysql-data:
+    name: nextchair-mysql-data
+
+networks:
+  nextchair-db:
+    name: nextchair-db
+    external: true