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

edge-agent/apps/onvif-exporter/Dockerfile

@@ -0,0 +1,12 @@
+# 多阶段构建：在镜像内编译，无需本机安装 Go
+FROM golang:1.21-alpine AS builder
+WORKDIR /app
+COPY apps/onvif-exporter/go.mod ./
+COPY apps/onvif-exporter/main.go ./
+RUN go mod tidy && CGO_ENABLED=0 GOOS=linux go build -o /onvif-exporter .
+
+FROM alpine:3.19
+RUN apk add --no-cache ca-certificates
+COPY --from=builder /onvif-exporter /onvif-exporter
+EXPOSE 9600
+ENTRYPOINT ["/onvif-exporter"]