feat: add monitoring agent (Go) + agent report API + cloud billing UI

- Go agent: CPU/mem/disk/port collectors, HTTP report, static binary
- Cross-compile: linux/amd64 + linux/arm64 (statically linked)
- One-line install script for all Linux distros
- Backend: POST /api/v1/agent/report (no JWT) + GET /agent/latest,history (JWT)
- CloudBilling.tsx: fixed syntax errors, stats/trends/records/alerts
- K8s menu renamed to Kubernetes管理

Signed-off-by: Logan.Li

agent/Makefile

@@ -0,0 +1,54 @@
+# Makefile for AIOps Agent
+# 提供本地构建、交叉编译及常用开发任务
+# 署名 Logan.Li
+
+APP        := aiops-agent
+VERSION    := 1.0.0
+BUILD_TIME := $(shell date -u +%Y-%m-%dT%H:%M:%SZ)
+# 注入版本信息；-s -w 去除调试符号以缩减二进制体积
+LDFLAGS    := -s -w -X main.version=$(VERSION) -X main.buildTime=$(BUILD_TIME)
+# 静态编译：关闭 CGO 并使用静态链接
+LINUX_LDFLAGS := -extldflags "-static"
+
+.PHONY: build cross build-linux-amd64 build-linux-arm64 tidy run fmt vet clean help
+
+## build: 本地构建当前平台二进制
+build:
+	go build -ldflags "$(LDFLAGS)" -o $(APP) .
+
+## cross: 交叉编译 Linux amd64 与 arm64（静态链接，适合容器/嵌入式部署）
+cross: build-linux-amd64 build-linux-arm64
+
+## build-linux-amd64: 交叉编译 linux/amd64
+build-linux-amd64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
+	go build -ldflags "$(LDFLAGS) $(LINUX_LDFLAGS)" -o bin/$(APP)-linux-amd64 .
+
+## build-linux-arm64: 交叉编译 linux/arm64
+build-linux-arm64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 \
+	go build -ldflags "$(LDFLAGS) $(LINUX_LDFLAGS)" -o bin/$(APP)-linux-arm64 .
+
+## tidy: 整理依赖
+tidy:
+	go mod tidy
+
+## run: 本地运行（默认连接 localhost:8080）
+run:
+	go run . -server http://localhost:8080 -interval 10
+
+## fmt: 格式化代码
+fmt:
+	go fmt ./...
+
+## vet: 静态检查
+vet:
+	go vet ./...
+
+## clean: 清理构建产物
+clean:
+	rm -rf bin $(APP)
+
+## help: 显示帮助
+help:
+	@grep -E '^## ' $(MAKEFILE_LIST) | sed 's/## //' | column -t -s ':'