feat: (re)add GoTomato.go

- refactor server package
  - update package name
  - rename `StartServer()` to `Start()`
- (re)add `GoTomato.go` to call `server.Start()`
- update README

GoTomato.go

@@ -0,0 +1,9 @@
+package main
+
+import (
+	"git.smsvc.net/pomodoro/GoTomato/cmd/server"
+)
+
+func main() {
+	server.Start()
+}

README.md

@@ -10,7 +10,7 @@ A pomodoro server written in Go
 
 ```
 docker run --rm -d --name pomodoro-client -v $PWD:/usr/share/nginx/html/ -p 8081:80 nginx
-go run ./cmd/server
+go run .
 ```
 
 open http://localhost:8081

cmd/server/main.go

@@ -1,4 +1,4 @@
-package main
+package server
 
 import (
 	"git.smsvc.net/pomodoro/GoTomato/internal/websocket"
@@ -6,7 +6,7 @@ import (
 	"net/http"
 )
 
-func main() {
+func Start() {
 	http.HandleFunc("/ws", websocket.HandleConnections)
 
 	log.Println("Pomodoro WebSocket server started on :8080")