chore: air hot-reload + configurable backend port for dev proxy

Makefile

@@ -1,4 +1,6 @@
-.PHONY: proto web server release dev test
+PORT ?= 8080  # порт бэка; в dev еще прокидывается в vite-прокси (BACKEND_PORT)
+
+.PHONY: proto web server release dev dev-srv dev-web watch test
 
 proto:  ## Regenerate Go + TS code from proto
 	PATH="$(shell go env GOPATH)/bin:$$PATH" protoc \
@@ -18,14 +20,17 @@ server:  ## Build Go binary → bin/hub-api
 release:  ## CI build: static binary for the box (run on the box itself, native arch)
 	CGO_ENABLED=0 go build -o bin/hub-api ./server
 
-dev:  ## Dev: Go server + Vite on :5173 (use http://localhost:5173)
-	go run ./server & cd web && pnpm dev
+dev:  ## Dev: Go server + Vite on :5173 (use http://localhost:5173); PORT=8081 make dev для второй копии
+	PORT=$(PORT) go run ./server & cd web && BACKEND_PORT=$(PORT) pnpm dev
 
 dev-srv:
-	go run ./server
+	PORT=$(PORT) go run ./server
 
 dev-web:
-	cd web && pnpm dev
+	cd web && BACKEND_PORT=$(PORT) pnpm dev
+
+watch:  ## Hot-reload сервера (air); порт как у dev: PORT=8081 make watch
+	PORT=$(PORT) air
 
 test:  ## Smoke-test the RPC endpoints
 	@go build -o bin/hub-api ./server