feat(web): initialize Next.js project with Tailwind CSS and TypeScript setup

Makefile

@@ -0,0 +1,39 @@
+.PHONY: build run serve test vet tidy clean web web-dev dev
+
+BINARY := bin/flow
+
+build: web
+	go build -o $(BINARY) ./cmd/flow
+
+# Build only the Go binary, expecting web/dist to already exist.
+build-go:
+	go build -o $(BINARY) ./cmd/flow
+
+web:
+	cd web && (test -d node_modules || npm install --no-fund --no-audit --loglevel=error) && npm run build
+
+web-dev:
+	cd web && (test -d node_modules || npm install --no-fund --no-audit --loglevel=error) && npm run dev
+
+# `make dev` runs the Vite dev server (auto-installs deps).
+# In another terminal run `make serve` to start the Go API on :8080;
+# the Vite proxy forwards /api/* requests to it.
+dev: web-dev
+
+serve: build-go
+	./$(BINARY) serve
+
+run: build
+	./$(BINARY)
+
+test:
+	go test ./... -count=1 -race
+
+vet:
+	go vet ./...
+
+tidy:
+	go mod tidy
+
+clean:
+	rm -rf bin/ web/dist web/node_modules *.db *.db-shm *.db-wal coverage.out