Zabbix supply backend rebuild + data-driven model supplies

Rewrite the printer Zabbix integration (Bearer auth, host-by-IP, tag-based
supply lookup, ping) and replace the hardcoded toner table with a
modelsupplies table + CRUD + seed. Add mock Zabbix server, live test
harness, and the Playwright screenshot tooling.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/docker-compose.zabbix.yml

@@ -0,0 +1,61 @@
+# Real Zabbix 7.0 server for full integration testing.
+#
+#   docker compose -f tools/docker-compose.zabbix.yml up -d
+#
+# Web UI: http://localhost:8888  (default login Admin / zabbix)
+# API:    http://localhost:8888/api_jsonrpc.php
+#
+# After it is up:
+#   1. Log in, go to Users > API tokens, create a token, copy it.
+#   2. Data collection > Hosts > Create host. Name the host by its IP
+#      (e.g. 10.20.30.40) so host.get filter {host:[ip]} finds it, the same
+#      way the production shop Zabbix names printer hosts.
+#   3. Add items tagged component=supplies, type=level, color=<color> to
+#      mirror the real printer templates (the mock server documents the shape).
+#   4. Point the app at it:
+#        ZABBIX_ENABLED=true
+#        ZABBIX_URL=http://localhost:8888
+#        ZABBIX_TOKEN=<token from step 1>
+#      or set zabbix_enabled / zabbix_url / zabbix_token in the settings table.
+#
+# For API-contract testing only, prefer tools/mock_zabbix.py - it needs no
+# image pulls and returns ready-made tagged supply items.
+
+services:
+  zabbix-postgres:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: zabbix
+      POSTGRES_PASSWORD: zabbixpass
+      POSTGRES_DB: zabbix
+    volumes:
+      - zabbix-pgdata:/var/lib/postgresql/data
+
+  zabbix-server:
+    image: zabbix/zabbix-server-pgsql:alpine-7.0-latest
+    environment:
+      DB_SERVER_HOST: zabbix-postgres
+      POSTGRES_USER: zabbix
+      POSTGRES_PASSWORD: zabbixpass
+      POSTGRES_DB: zabbix
+    depends_on:
+      - zabbix-postgres
+    ports:
+      - "10051:10051"
+
+  zabbix-web:
+    image: zabbix/zabbix-web-nginx-pgsql:alpine-7.0-latest
+    environment:
+      DB_SERVER_HOST: zabbix-postgres
+      POSTGRES_USER: zabbix
+      POSTGRES_PASSWORD: zabbixpass
+      POSTGRES_DB: zabbix
+      ZBX_SERVER_HOST: zabbix-server
+      PHP_TZ: America/New_York
+    depends_on:
+      - zabbix-server
+    ports:
+      - "8888:8080"
+
+volumes:
+  zabbix-pgdata: