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

doc/BEST_PRACTICES.md

@@ -164,11 +164,8 @@ firewall-cmd --reload
 ```bash
 # 备份所有配置文件
 tar -czf config-backup-$(date +%Y%m%d).tar.gz \
-  central-server/*.yml \
-  central-server/alertmanager/*.yml \
-  central-server/grafana/provisioning/ \
-  edge-agent/*.yml \
-  edge-agent/prometheus-edge/*.yml
+  central-server/config/ \
+  edge-agent/config/
 ```
 
 #### 数据备份