refactor: move backend files to backend/ directory

Reorganize project structure:
- backend/cmd/openteam/ — entry point
- backend/internal/ — core packages
- backend/middleware/ — HTTP middleware
- backend/router/ — route setup
- backend/wire/ — dependency injection
- backend/pkg/ — shared utilities
- backend/go.mod, go.sum — Go module files

Updated Makefile to work from backend/ directory.
Removed old lowercase makefile.

Makefile

@@ -2,10 +2,11 @@
 
 BINARY_NAME=openteam
 BUILD_DIR=bin
+BACKEND_DIR=backend
 
 # Build
 build:
-	go build -o $(BUILD_DIR)/$(BINARY_NAME) ./cmd/openteam
+	cd $(BACKEND_DIR) && CGO_ENABLED=1 go build -o ../$(BUILD_DIR)/$(BINARY_NAME) ./cmd/openteam
 
 # Run
 run: build
@@ -13,41 +14,41 @@ run: build
 
 # Development run
 dev:
-	go run ./cmd/openteam
+	cd $(BACKEND_DIR) && go run ./cmd/openteam
 
 # Test
 test:
-	go test ./internal/... -v
+	cd $(BACKEND_DIR) && go test ./internal/... -v
 
 # Test with coverage
 test-cover:
-	go test ./internal/... -coverprofile=coverage.out
-	go tool cover -html=coverage.out -o coverage.html
+	cd $(BACKEND_DIR) && go test ./internal/... -coverprofile=coverage.out
+	cd $(BACKEND_DIR) && go tool cover -html=coverage.out -o coverage.html
 
 # Format code
 fmt:
-	go fmt ./...
+	cd $(BACKEND_DIR) && go fmt ./...
 
 # Lint
 lint:
-	golangci-lint run
+	cd $(BACKEND_DIR) && golangci-lint run
 
 # Clean
 clean:
 	rm -rf $(BUILD_DIR)
-	rm -f coverage.out coverage.html
+	cd $(BACKEND_DIR) && rm -f coverage.out coverage.html
 
 # Tidy dependencies
 tidy:
-	go mod tidy
+	cd $(BACKEND_DIR) && go mod tidy
 
 # Build for Linux
 build-linux:
-	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o $(BUILD_DIR)/$(BINARY_NAME)-linux-amd64 ./cmd/openteam
+	cd $(BACKEND_DIR) && CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o ../$(BUILD_DIR)/$(BINARY_NAME)-linux-amd64 ./cmd/openteam
 
 # Build for macOS
 build-mac:
-	CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 go build -o $(BUILD_DIR)/$(BINARY_NAME)-darwin-arm64 ./cmd/openteam
+	cd $(BACKEND_DIR) && CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 go build -o ../$(BUILD_DIR)/$(BINARY_NAME)-darwin-arm64 ./cmd/openteam
 
 # Build all platforms
 build-all: build-linux build-mac

makefile

@@ -1,96 +0,0 @@
-GOPATH:=$(shell go env GOPATH)
-VERSION=$(shell git describe --tags --always)
-# 获取源码最近一次 git commit log，包含 commit sha 值，以及 commit message
-GitCommitLog=$(shell git log)
-# 检查源码在最近一次 git commit 基础上，是否有本地修改，且未提交的文件
-GitStatus=$(shell git status -s)
-# 获取当前时间
-BuildTime=$(shell date +'%Y.%m.%d %H:%M:%S')
-# 获取Go的版本
-BuildGoVersion=$(shell go version)
-
-LDFlags=" \
--X 'main.Version=$(VERSION)' \
--X 'main.GitCommitLog=$(GitCommitLog)' \
--X 'main.BuildTime=$(BuildTime)' \
--X 'main.BuildGoVersion=$(BuildGoVersion)'"
-
-.PHONY: web
-# 构建前端并放入 Go embed 目录 (cmd/openteam/dist)
-web:
-	cd frontend && (command -v pnpm >/dev/null 2>&1 || npm install -g pnpm) && pnpm install --frozen-lockfile && pnpm build
-	rm -rf cmd/openteam/dist
-	mkdir -p cmd/openteam
-	mv frontend/dist cmd/openteam/dist
-	touch cmd/openteam/dist/.gitkeep
-
-.PHONY: dev-backend
-# 本地启动后端 (端口 8080, 数据库 ./db/openteam.db)
-dev-backend:
-	PORT=8080 go run ./cmd/openteam
-
-.PHONY: dev-frontend
-# 本地启动前端 dev server (端口 5173, /api 代理到后端)
-dev-frontend:
-	cd frontend && pnpm dev
-
-.PHONY: dev
-# 并行启动前后端本地开发环境 (Ctrl+C 一起退出)
-dev:
-	$(MAKE) -j2 dev-backend dev-frontend
-
-.PHONY: build
-# build
-build:
-# mkdir -p bin/ && go build -ldflags $(LDFlags) -o ./bin/ ./...
-	rm -rf  bin
-	mkdir -p bin/  &&  CGO_ENABLED=0 go build -ldflags "-s -w" -o ./bin/openteam ./cmd/openteam/
-	command -v upx >/dev/null 2>&1 && upx -9 bin/openteam || echo "upx 未安装，跳过二进制压缩"
-
-.PHONY:image
-# build docker images
-image:
-	docker build -t mirrors2/opencatd-open:latest -f deploy/docker/Dockerfile . --push
-
-.PHONY:docker
-# build docker images
-docker:
-	docker run --privileged --rm tonistiigi/binfmt --install all
-# docker buildx create --use --name xbuilder --driver docker-container
-	docker buildx inspect xbuilder --bootstrap
-	docker buildx build --platform linux/amd64,linux/arm64 -t mirrors2/opencatd-open:latest -f deploy/docker/Dockerfile . --push
-
-.PHONY:image-dev
-# build & push multi-arch dev image (PUSH=0 仅本地加载本机架构)
-image-dev:
-	sh deploy/docker/build-dev.sh
-
-.PHONY: clean
-# clean
-clean:
-	rm -rf bin/
-
-.PHONY: all
-# generate all
-all:
-	make build;
-
-
-# show help
-help:
-	@echo ''
-	@echo 'Usage:'
-	@echo ' make [target]'
-	@echo ''
-	@echo 'Targets:'
-	@awk '/^[a-zA-Z\-\_0-9]+:/ { \
-	helpMessage = match(lastLine, /^# (.*)/); \
-		if (helpMessage) { \
-			helpCommand = substr($$1, 0, index($$1, ":")-1); \
-			helpMessage = substr(lastLine, RSTART + 2, RLENGTH); \
-			printf "\033[36m%-22s\033[0m %s\n", helpCommand,helpMessage; \
-		} \
-	} \
-	{ lastLine = $$0 }' $(MAKEFILE_LIST)
-
-.DEFAULT_GOAL := help