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

.gitignore

@@ -2,7 +2,6 @@ central-server/data/
 central-server/.env
 
 edge-agent/.env
-edge-agent/prometheus-edge/data/
 
 # 生成文件（由 update-configs.sh 从 targets.csv 生成）
 edge-agent/config/*.json