fix: restrict Model Pricing table to used models and fix cost stats

Implemented used_only filter for /api/models. Added missing cache token and cost fields to usage summary and provider usage endpoints.

internal/server/dashboard.go

@@ -224,15 +224,19 @@ func (s *Server) handleUsageSummary(c *gin.Context) {
 	
 	// Total stats
 	var totalStats struct {
-		TotalRequests int     `db:"total_requests"`
-		TotalTokens   int     `db:"total_tokens"`
-		TotalCost     float64 `db:"total_cost"`
-		ActiveClients int     `db:"active_clients"`
+		TotalRequests    int     `db:"total_requests"`
+		TotalTokens      int     `db:"total_tokens"`
+		CacheReadTokens  int     `db:"total_cache_read_tokens"`
+		CacheWriteTokens int     `db:"total_cache_write_tokens"`
+		TotalCost        float64 `db:"total_cost"`
+		ActiveClients    int     `db:"active_clients"`
 	}
 	err := s.database.Get(&totalStats, fmt.Sprintf(`
 		SELECT 
 			COUNT(*) as total_requests,
 			COALESCE(SUM(total_tokens), 0) as total_tokens,
+			COALESCE(SUM(cache_read_tokens), 0) as total_cache_read_tokens,
+			COALESCE(SUM(cache_write_tokens), 0) as total_cache_write_tokens,
 			COALESCE(SUM(cost), 0.0) as total_cost,
 			COUNT(DISTINCT client_id) as active_clients
 		FROM llm_requests
@@ -257,7 +261,6 @@ func (s *Server) handleUsageSummary(c *gin.Context) {
 		WHERE timestamp LIKE ?
 	`, today+"%")
 	if err != nil {
-		fmt.Printf("[ERROR] Failed to fetch today stats: %v\n", err)
 		todayStats.TodayRequests = 0
 		todayStats.TodayCost = 0.0
 	}
@@ -279,14 +282,16 @@ func (s *Server) handleUsageSummary(c *gin.Context) {
 	}
 
 	c.JSON(http.StatusOK, SuccessResponse(gin.H{
-		"total_requests":    totalStats.TotalRequests,
-		"total_tokens":      totalStats.TotalTokens,
-		"total_cost":        totalStats.TotalCost,
-		"active_clients":    totalStats.ActiveClients,
-		"today_requests":    todayStats.TodayRequests,
-		"today_cost":        todayStats.TodayCost,
-		"error_rate":        miscStats.ErrorRate,
-		"avg_response_time": miscStats.AvgResponseTime,
+		"total_requests":           totalStats.TotalRequests,
+		"total_tokens":             totalStats.TotalTokens,
+		"total_cache_read_tokens":  totalStats.CacheReadTokens,
+		"total_cache_write_tokens": totalStats.CacheWriteTokens,
+		"total_cost":               totalStats.TotalCost,
+		"active_clients":           totalStats.ActiveClients,
+		"today_requests":           todayStats.TodayRequests,
+		"today_cost":               todayStats.TodayCost,
+		"error_rate":               miscStats.ErrorRate,
+		"avg_response_time":        miscStats.AvgResponseTime,
 	}))
 }
 
@@ -307,7 +312,6 @@ func (s *Server) handleTimeSeries(c *gin.Context) {
 	query := fmt.Sprintf(`
 		SELECT 
 			COALESCE(SUBSTR(timestamp, 1, 10), 'unknown') as bucket,
-
 			COUNT(*) as requests,
 			COALESCE(SUM(total_tokens), 0) as tokens,
 			COALESCE(SUM(cost), 0.0) as cost
@@ -357,7 +361,10 @@ func (s *Server) handleProvidersUsage(c *gin.Context) {
 	clause, binds := filter.ToSQL()
 
 	rows, err := s.database.Queryx(fmt.Sprintf(`
-		SELECT COALESCE(provider, 'unknown') as provider, COUNT(*) as requests
+		SELECT 
+			COALESCE(provider, 'unknown') as provider, 
+			COUNT(*) as requests,
+			COALESCE(SUM(cost), 0.0) as cost
 		FROM llm_requests
 		WHERE 1=1 %s
 		GROUP BY provider
@@ -372,8 +379,9 @@ func (s *Server) handleProvidersUsage(c *gin.Context) {
 	for rows.Next() {
 		var provider string
 		var requests int
-		if err := rows.Scan(&provider, &requests); err == nil {
-			results = append(results, gin.H{"provider": provider, "requests": requests})
+		var cost float64
+		if err := rows.Scan(&provider, &requests, &cost); err == nil {
+			results = append(results, gin.H{"provider": provider, "requests": requests, "cost": cost})
 		}
 	}
 
@@ -944,6 +952,8 @@ func (s *Server) handleTestProvider(c *gin.Context) {
 }
 
 func (s *Server) handleGetModels(c *gin.Context) {
+	usedOnly := c.Query("used_only") == "true"
+
 	// Merge registry models with DB overrides
 	var dbModels []db.ModelConfig
 	_ = s.database.Select(&dbModels, "SELECT * FROM model_configs")
@@ -953,10 +963,30 @@ func (s *Server) handleGetModels(c *gin.Context) {
 		dbMap[m.ID] = m
 	}
 
+	// Fetch set of used model IDs if requested
+	usedModels := make(map[string]bool)
+	if usedOnly {
+		rows, err := s.database.Queryx("SELECT DISTINCT model FROM llm_requests")
+		if err == nil {
+			for rows.Next() {
+				var mID string
+				if err := rows.Scan(&mID); err == nil {
+					usedModels[mID] = true
+				}
+			}
+			rows.Close()
+		}
+	}
+
 	var result []gin.H
 	if s.registry != nil {
 		for pID, pInfo := range s.registry.Providers {
 			for mID, mMeta := range pInfo.Models {
+				// Filter if used_only requested
+				if usedOnly && !usedModels[mID] {
+					continue
+				}
+
 				enabled := true
 				promptCost := 0.0
 				completionCost := 0.0