phase4: templUI-based frontend with HTMX-powered conversion form

Makefile

@@ -1,5 +1,7 @@
 VERSION := $(shell cat VERSION)
 LDFLAGS := -X github.com/fserg/md-to-html/internal/version.Version=$(VERSION)
+GOBIN := $(shell go env GOPATH)/bin
+TEMPL := $(GOBIN)/templ
 
 .PHONY: build run test templ tailwind dev docker clean tools
 
@@ -13,13 +15,18 @@ test:
 	go test ./...
 
 templ:
-	templ generate
+	$(TEMPL) generate ./...
 
 tailwind:
-	@echo "tailwind target will be implemented in phase 4"
+	mkdir -p web/static/dist
+	npx tailwindcss -i web/static/src/app.css -o web/static/dist/app.css --minify
 
 dev:
-	@echo "dev target will be implemented in phase 4"
+	mkdir -p web/static/dist
+	sh -c 'npx tailwindcss -i web/static/src/app.css -o web/static/dist/app.css --watch & \
+	TAILWIND_PID=$$!; \
+	trap "kill $$TAILWIND_PID" EXIT INT TERM; \
+	$(TEMPL) generate --watch --proxy=http://localhost:8080 --cmd="go run ./cmd/md-to-html serve"'
 
 docker:
 	@echo "docker target will be implemented in phase 6"
@@ -29,3 +36,4 @@ clean:
 
 tools:
 	go install github.com/a-h/templ/cmd/templ@v0.3.1001
+	go install github.com/templui/templui/cmd/templui@latest