feat: migrate backend from rust to go

This commit replaces the Axum/Rust backend with a Gin/Go implementation. The original Rust code has been archived in the 'rust' branch.

internal/server/websocket.go

@@ -0,0 +1,98 @@
+package server
+
+import (
+	"log"
+	"net/http"
+	"sync"
+
+	"github.com/gin-gonic/gin"
+	"github.com/gorilla/websocket"
+)
+
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  1024,
+	WriteBufferSize: 1024,
+	CheckOrigin: func(r *http.Request) bool {
+		return true // In production, refine this
+	},
+}
+
+type Hub struct {
+	clients    map[*websocket.Conn]bool
+	broadcast  chan interface{}
+	register   chan *websocket.Conn
+	unregister chan *websocket.Conn
+	mu         sync.Mutex
+}
+
+func NewHub() *Hub {
+	return &Hub{
+		clients:    make(map[*websocket.Conn]bool),
+		broadcast:  make(chan interface{}),
+		register:   make(chan *websocket.Conn),
+		unregister: make(chan *websocket.Conn),
+	}
+}
+
+func (h *Hub) Run() {
+	for {
+		select {
+		case client := <-h.register:
+			h.mu.Lock()
+			h.clients[client] = true
+			h.mu.Unlock()
+			log.Println("WebSocket client registered")
+		case client := <-h.unregister:
+			h.mu.Lock()
+			if _, ok := h.clients[client]; ok {
+				delete(h.clients, client)
+				client.Close()
+			}
+			h.mu.Unlock()
+			log.Println("WebSocket client unregistered")
+		case message := <-h.broadcast:
+			h.mu.Lock()
+			for client := range h.clients {
+				err := client.WriteJSON(message)
+				if err != nil {
+					log.Printf("WebSocket error: %v", err)
+					client.Close()
+					delete(h.clients, client)
+				}
+			}
+			h.mu.Unlock()
+		}
+	}
+}
+
+func (s *Server) handleWebSocket(c *gin.Context) {
+	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
+	if err != nil {
+		log.Printf("Failed to set websocket upgrade: %v", err)
+		return
+	}
+
+	s.hub.register <- conn
+
+	defer func() {
+		s.hub.unregister <- conn
+	}()
+
+	// Initial message
+	conn.WriteJSON(gin.H{
+		"type":    "connected",
+		"message": "Connected to LLM Proxy Dashboard",
+	})
+
+	for {
+		var msg map[string]interface{}
+		err := conn.ReadJSON(&msg)
+		if err != nil {
+			break
+		}
+		
+		if msg["type"] == "ping" {
+			conn.WriteJSON(gin.H{"type": "pong", "payload": gin.H{}})
+		}
+	}
+}