feat: implement system metrics and fix monitoring charts

Added /api/system/metrics with CPU/Mem/Disk/Load data using gopsutil. Updated Hub to track active WebSocket listeners. Verified log format for monitoring charts.

internal/server/dashboard.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"fmt"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -12,6 +13,12 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/google/uuid"
 	"golang.org/x/crypto/bcrypt"
+
+	"github.com/shirou/gopsutil/v3/cpu"
+	"github.com/shirou/gopsutil/v3/mem"
+	"github.com/shirou/gopsutil/v3/disk"
+	"github.com/shirou/gopsutil/v3/load"
+	"github.com/shirou/gopsutil/v3/process"
 )
 
 type ApiResponse struct {
@@ -955,7 +962,6 @@ func (s *Server) handleGetModels(c *gin.Context) {
 	usedOnly := c.Query("used_only") == "true"
 
 	// Registry provider normalized name -> Proxy-internal provider ID
-	// This ensures we only show models from YOUR providers.
 	allowedRegistryProviders := map[string]string{
 		"openai":   "openai",
 		"google":   "gemini",
@@ -983,7 +989,6 @@ func (s *Server) handleGetModels(c *gin.Context) {
 		err := s.database.Select(&pairs, "SELECT DISTINCT model, provider FROM llm_requests WHERE status = 'success'")
 		if err == nil {
 			for _, p := range pairs {
-				// Key format: "gpt-4o:openai"
 				usedPairs[fmt.Sprintf("%s:%s", p.Model, p.Provider)] = true
 			}
 		}
@@ -992,14 +997,12 @@ func (s *Server) handleGetModels(c *gin.Context) {
 	var result []gin.H
 	if s.registry != nil {
 		for pID, pInfo := range s.registry.Providers {
-			// Only include models from the 4 allowed registry IDs
 			proxyProvider, allowed := allowedRegistryProviders[pID]
 			if !allowed {
 				continue
 			}
 
 			for mID, mMeta := range pInfo.Models {
-				// If usedOnly is true, only include if this exact (model, provider) was logged
 				if usedOnly && !usedPairs[fmt.Sprintf("%s:%s", mID, proxyProvider)] {
 					continue
 				}
@@ -1043,7 +1046,7 @@ func (s *Server) handleGetModels(c *gin.Context) {
 				result = append(result, gin.H{
 					"id":               mID,
 					"name":             mMeta.Name,
-					"provider":         proxyProvider, // Correctly normalized provider name
+					"provider":         proxyProvider,
 					"enabled":          enabled,
 					"prompt_cost":      promptCost,
 					"completion_cost":  completionCost,
@@ -1218,6 +1221,42 @@ func (s *Server) handleSystemHealth(c *gin.Context) {
 	}))
 }
 
+func (s *Server) handleSystemMetrics(c *gin.Context) {
+	v, _ := mem.VirtualMemory()
+	c_usage, _ := cpu.Percent(time.Second, false)
+	d, _ := disk.Usage("/")
+	l, _ := load.Avg()
+	p, _ := process.NewProcess(int32(os.Getpid()))
+	rss, _ := p.MemoryInfo()
+
+	cpuPercent := 0.0
+	if len(c_usage) > 0 {
+		cpuPercent = c_usage[0]
+	}
+
+	c.JSON(http.StatusOK, SuccessResponse(gin.H{
+		"cpu": gin.H{
+			"usage_percent": fmt.Sprintf("%.1f", cpuPercent),
+			"load_average":  []float64{l.Load1, l.Load5, l.Load15},
+		},
+		"memory": gin.H{
+			"used_mb":        v.Used / 1024 / 1024,
+			"total_mb":       v.Total / 1024 / 1024,
+			"usage_percent":  fmt.Sprintf("%.1f", v.UsedPercent),
+			"process_rss_mb": rss.RSS / 1024 / 1024,
+		},
+		"disk": gin.H{
+			"used_gb":       float64(d.Used) / 1024 / 1024 / 1024,
+			"total_gb":      float64(d.Total) / 1024 / 1024 / 1024,
+			"usage_percent": fmt.Sprintf("%.1f", d.UsedPercent),
+		},
+		"connections": gin.H{
+			"db_active":           s.database.Stats().OpenConnections,
+			"websocket_listeners": s.hub.GetClientCount(),
+		},
+	}))
+}
+
 func (s *Server) handleGetSettings(c *gin.Context) {
 	providerCount := 0
 	modelCount := 0
@@ -1268,6 +1307,7 @@ func (s *Server) handleGetLogs(c *gin.Context) {
 		Model     string `json:"model"`
 		Tokens    int    `json:"tokens"`
 		Status    string `json:"status"`
+		Duration  int    `json:"duration"`
 	}
 
 	uiLogs := make([]UILog, len(logs))
@@ -1288,6 +1328,10 @@ func (s *Server) handleGetLogs(c *gin.Context) {
 		if l.TotalTokens != nil {
 			tokens = *l.TotalTokens
 		}
+		duration := 0
+		if l.DurationMS != nil {
+			duration = *l.DurationMS
+		}
 
 		uiLogs[i] = UILog{
 			Timestamp: l.Timestamp.Format(time.RFC3339),
@@ -1296,6 +1340,7 @@ func (s *Server) handleGetLogs(c *gin.Context) {
 			Model:     model,
 			Tokens:    tokens,
 			Status:    l.Status,
+			Duration:  duration,
 		}
 	}