chore: streamline workspace make workflows

Clarify product-level server and desktop commands while moving backend-only maintenance tasks into backend/Makefile. This keeps root automation focused on core flows and aligns the main OpenSpec specs with the new command boundaries.

backend/Makefile

@@ -0,0 +1,97 @@
+.PHONY: \
+	build run \
+	test test-unit test-integration test-coverage \
+	lint clean \
+	migrate-up migrate-down migrate-status migrate-create \
+	mysql-up mysql-down mysql-test mysql-test-quick
+
+VERSION := $(shell go run ./cmd/versionctl print)
+GIT_COMMIT ?= $(shell git rev-parse --short HEAD 2>/dev/null || printf 'unknown')
+BUILD_TIME ?= $(shell date -u +"%Y-%m-%dT%H:%M:%SZ")
+GO_LDFLAGS := -X nex/backend/pkg/buildinfo.version=$(VERSION) -X nex/backend/pkg/buildinfo.commit=$(GIT_COMMIT) -X nex/backend/pkg/buildinfo.buildTime=$(BUILD_TIME)
+
+DB_DRIVER ?= sqlite3
+DB_DSN ?= $(HOME)/.nex/config.db
+
+ifeq ($(DB_DRIVER),mysql)
+GOOSE_DIR := migrations/mysql
+GOOSE_DRIVER := mysql
+else ifeq ($(DB_DRIVER),sqlite3)
+GOOSE_DIR := migrations/sqlite
+GOOSE_DRIVER := sqlite3
+else
+$(error unsupported DB_DRIVER '$(DB_DRIVER)', use sqlite3 or mysql)
+endif
+
+build:
+	go build -ldflags "$(GO_LDFLAGS)" -o bin/server ./cmd/server
+
+run:
+	go run -ldflags "$(GO_LDFLAGS)" ./cmd/server
+
+test:
+	go test ./internal/... ./pkg/... ./tests/... ./cmd/server/... -v
+
+test-unit:
+	go test ./internal/... ./pkg/... -v
+
+test-integration:
+	go test ./tests/... -v
+
+test-coverage:
+	go test ./... -coverprofile=coverage.out
+	go tool cover -html=coverage.out -o coverage.html
+	@printf 'Coverage report generated: backend/coverage.html\n'
+
+lint:
+	go tool golangci-lint run ./...
+
+clean:
+	rm -rf bin/ coverage.out coverage.html
+
+migrate-up:
+	@printf 'Running database migration up...\n'
+	goose -dir $(GOOSE_DIR) $(GOOSE_DRIVER) "$(DB_DSN)" up
+
+migrate-down:
+	@printf 'Running database migration down...\n'
+	goose -dir $(GOOSE_DIR) $(GOOSE_DRIVER) "$(DB_DSN)" down
+
+migrate-status:
+	@printf 'Checking database migration status...\n'
+	goose -dir $(GOOSE_DIR) $(GOOSE_DRIVER) "$(DB_DSN)" status
+
+migrate-create:
+	@printf 'Migration name: '; \
+	read name; \
+	goose -dir migrations/sqlite create $$name sql; \
+	goose -dir migrations/mysql create $$name sql
+
+mysql-up:
+	@printf 'Starting MySQL test container...\n'
+	cd tests/mysql && docker-compose up -d
+	@printf 'Waiting for MySQL to be ready...\n'
+	@for i in $$(seq 1 30); do \
+		if docker exec nex-mysql-test mysqladmin ping -h localhost -u root -ptestpass --silent 2>/dev/null; then \
+			printf 'MySQL is ready\n'; \
+			exit 0; \
+		fi; \
+		printf 'Waiting... (%s/30)\n' $$i; \
+		sleep 1; \
+	done; \
+	printf 'MySQL failed to start\n'; \
+	exit 1
+
+mysql-down:
+	@printf 'Stopping MySQL test container...\n'
+	cd tests/mysql && docker-compose down -v
+
+mysql-test:
+	@set -e; \
+	$(MAKE) mysql-up; \
+	trap '$(MAKE) mysql-down' EXIT; \
+	go test -tags=mysql ./tests/mysql/... -v -count=1
+
+mysql-test-quick:
+	@printf 'Running MySQL tests without container management...\n'
+	go test -tags=mysql ./tests/mysql/... -v -count=1