chore: add install/build targets and split dev/prod server commands

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Makefile

@@ -2,32 +2,61 @@
 -include .env
 export
 
-.PHONY: docker-up docker-down migrate-up migrate-down \
+.PHONY: install build \
-        run-backend run-frontend test test-coverage lint seed
+        docker-up docker-down migrate-up migrate-down \
+        run-backend run-frontend \
+        dev-backend dev-frontend \
+        test test-coverage lint seed
+
+## ── Setup ────────────────────────────────────────────────────────────────────
+
+# Install all dependencies: Go CLI tools, Go modules, Node packages.
+install:
+	go install github.com/pressly/goose/v3/cmd/goose@latest
+	go install github.com/air-verse/air@latest
+	cd backend && go mod download
+	cd frontend && npm ci
+
+# Build the Go binary and the Next.js production bundle.
+build:
+	mkdir -p backend/bin
+	cd backend && go build -o bin/api ./cmd/api
+	cd frontend && npm run build
+
+## ── Infrastructure ───────────────────────────────────────────────────────────
 
-## Infrastructure
 docker-up:
 	docker compose up -d postgres redis
 
 docker-down:
 	docker compose down
 
-## Migrations (requires goose: go install github.com/pressly/goose/v3/cmd/goose@latest)
 migrate-up:
 	PATH=$$HOME/go/bin:$$PATH goose -dir migrations postgres "$(DATABASE_URL)" up
 
 migrate-down:
 	PATH=$$HOME/go/bin:$$PATH goose -dir migrations postgres "$(DATABASE_URL)" down
 
-## Development servers
+## ── Production servers (require `make build` first) ─────────────────────────
+
+# Run the compiled Go binary.
 run-backend:
+	cd backend && ./bin/api
+
+# Run the Next.js production server on port 3001.
+run-frontend:
+	cd frontend && env -u PORT npx next start -p 3001
+
+## ── Development servers (hot reload) ────────────────────────────────────────
+
+dev-backend:
 	cd backend && PATH=$$HOME/go/bin:$$PATH air
 
-# PORT is exported from .env (backend uses it); unset it so Next.js defaults to 3000.
+dev-frontend:
-run-frontend:
 	cd frontend && env -u PORT npm run dev
 
-## Testing
+## ── Testing ──────────────────────────────────────────────────────────────────
+
 test:
 	cd backend && go test ./... && cd ../frontend && npm test -- --passWithNoTests
 
@@ -35,11 +64,13 @@ test-coverage:
 	cd backend && go test -coverprofile=coverage.out ./... && go tool cover -html=coverage.out -o coverage.html
 	@echo "Coverage report: backend/coverage.html"
 
-## Dev seed (local DB only — never run against production)
+## ── Dev seed (local DB only — never run against production) ──────────────────
+
 seed:
 	cd backend && go run ./cmd/seed
 
-## Linting
+## ── Linting ──────────────────────────────────────────────────────────────────
+
 lint:
 	cd backend && golangci-lint run ./...
 	cd frontend && npx tsc --noEmit && npx eslint .