refactor: config/apps 目录重组、文档重构、架构图收窄

- 中央：config/(prometheus,alertmanager,grafana)、apps/(tile-cache,topology-editor)
- 边缘：config/(vmagent,blackbox,targets)、apps/(onvif-exporter)
- env: TRAEFIK_PROVIDER、prometheus/env.example 详细说明
- 文档：README/doc 重构，EDGE_CACHE 合并到 EDGE_AGENT_CONFIG
- targets.csv 更新流程说明，ARCHITECTURE 图收窄

Made-with: Cursor

central-server/apps/tile-cache/Dockerfile

@@ -0,0 +1,7 @@
+FROM node:20-alpine
+WORKDIR /app
+COPY apps/tile-cache/package.json apps/tile-cache/server.js ./
+RUN mkdir -p /app/cache
+ENV PORT=4090
+EXPOSE 4090
+CMD ["node", "server.js"]