fix(make): пересобирать изменившийся фронтенд в make run

Цель run зависела только от backend, а статика фронтенда попадает в бинарник
через go:embed из backend/static, который обновляла лишь цель frontend. Поэтому
make run пересобирал Go-код со старым UI.

- run теперь зависит от frontend backend;
- frontend стала инкрементальной: npm ci только при изменении package.json/
  package-lock.json, npm run build и копирование в backend/static — только когда
  исходники или конфиги новее, чем backend/static/index.html (он же stamp);
- проверки вынесены в shell-recipe, т.к. имена SvelteKit-роутов вида (app)
  ломают разбор имён файлов в make.

Makefile

@@ -32,10 +32,44 @@ help:
 	@echo "Available targets:"
 	@grep -hE '^[a-zA-Z0-9_-]+:' $(MAKEFILE_LIST) | cut -d: -f1 | sed 's/^/  /'
 
+# Frontend sources whose changes must trigger a rebuild. `backend/static/index.html`
+# doubles as the build stamp, so a clean clone or `make clean` (which empties
+# backend/static) forces the next build to regenerate.
+FRONTEND_OUT := backend/static/index.html
+
+# `npm ci` is only needed when the manifest/lockfile change.
+FRONTEND_DEPS_STAMP := frontend/node_modules/.install-stamp
+
+# Build the SvelteKit bundle and copy it into backend/static (embedded via
+# go:embed). Incremental: recompile only when frontend sources are newer than the
+# embedded bundle. Paths are checked from the recipe (not as make prerequisites)
+# because SvelteKit route names like `(app)` break make's filename parsing.
 frontend:
-	cd frontend && npm ci && npm run build
-	rm -rf backend/static/*
-	cp -r frontend/build/* backend/static/
+	@set -e; \
+	if [ ! -f $(FRONTEND_DEPS_STAMP) ] \
+		|| [ frontend/package.json -nt $(FRONTEND_DEPS_STAMP) ] \
+		|| [ frontend/package-lock.json -nt $(FRONTEND_DEPS_STAMP) ]; then \
+		echo '> cd frontend && npm ci'; \
+		cd frontend && npm ci; \
+		touch node_modules/.install-stamp; \
+		cd ..; \
+	fi; \
+	if [ ! -f $(FRONTEND_OUT) ] \
+		|| [ -n "$$(find frontend/src frontend/static -newer $(FRONTEND_OUT) -print -quit)" ] \
+		|| [ frontend/package.json -nt $(FRONTEND_OUT) ] \
+		|| [ frontend/package-lock.json -nt $(FRONTEND_OUT) ] \
+		|| [ frontend/svelte.config.js -nt $(FRONTEND_OUT) ] \
+		|| [ frontend/vite.config.ts -nt $(FRONTEND_OUT) ] \
+		|| [ frontend/tailwind.config.ts -nt $(FRONTEND_OUT) ] \
+		|| [ frontend/tsconfig.json -nt $(FRONTEND_OUT) ]; then \
+		echo '> cd frontend && npm run build'; \
+		cd frontend && npm run build; \
+		cd ..; \
+		rm -rf backend/static/*; \
+		cp -r frontend/build/* backend/static/; \
+	else \
+		echo 'frontend: up to date'; \
+	fi
 
 backend:
 	mkdir -p bin
@@ -87,7 +121,7 @@ build-release: frontend
 	cp bin/galo bin/galo-$(VERSION)
 	@echo "release: bin/galo-$(VERSION)"
 
-run: backend
+run: frontend backend
 	./bin/galo
 
 migrate: