feat(ci): add deploy workflow and Makefile

- Add .gitea/workflows/deploy.yml for CD pipeline
- Add Makefile for build automation
- Update .gitignore to exclude docs/

Makefile

@@ -0,0 +1,59 @@
+.PHONY: build test run docker docker-push clean help
+
+APP_NAME := carrot_bbs
+VERSION := $(shell git rev-parse --short HEAD 2>/dev/null || echo "dev")
+BUILD_TIME := $(shell date -u '+%Y-%m-%d_%H:%M:%S')
+LDFLAGS := -ldflags "-s -w -X main.Version=$(VERSION) -X main.BuildTime=$(BUILD_TIME)"
+
+REGISTRY := code.littlelan.cn
+IMAGE_NAME := carrot_bbs/backend
+
+help:
+	@echo "Available targets:"
+	@echo "  make build        - Build the binary"
+	@echo "  make test         - Run tests"
+	@echo "  make run          - Run locally"
+	@echo "  make docker       - Build Docker image"
+	@echo "  make docker-push  - Push Docker image to registry"
+	@echo "  make clean        - Clean build artifacts"
+
+build:
+	@echo "Building $(APP_NAME)..."
+	CGO_ENABLED=0 go build $(LDFLAGS) -o server ./cmd/server
+
+test:
+	@echo "Running tests..."
+	go test -v -race -coverprofile=coverage.out ./...
+	go tool cover -html=coverage.out -o coverage.html
+
+run:
+	@echo "Running $(APP_NAME)..."
+	go run ./cmd/server
+
+docker:
+	@echo "Building Docker image..."
+	docker build -t $(REGISTRY)/$(IMAGE_NAME):$(VERSION) -t $(REGISTRY)/$(IMAGE_NAME):latest .
+
+docker-push:
+	@echo "Pushing Docker image..."
+	docker push $(REGISTRY)/$(IMAGE_NAME):$(VERSION)
+	docker push $(REGISTRY)/$(IMAGE_NAME):latest
+
+clean:
+	@echo "Cleaning..."
+	rm -f server
+	rm -f coverage.out coverage.html
+	go clean
+
+lint:
+	@echo "Running linter..."
+	golangci-lint run ./...
+
+fmt:
+	@echo "Formatting code..."
+	go fmt ./...
+	goimports -w .
+
+wire:
+	@echo "Generating wire..."
+	cd cmd/server && wire