fix: restrict Model Pricing table to core providers and actual usage

Filtered registry iteration to only include openai, gemini, deepseek, and grok. Improved used_only logic to match specific (model, provider) pairs from logs.

internal/server/dashboard.go

@@ -954,9 +954,12 @@ func (s *Server) handleTestProvider(c *gin.Context) {
 func (s *Server) handleGetModels(c *gin.Context) {
 	usedOnly := c.Query("used_only") == "true"
 
-	// Provider name mapping (Registry -> Proxy)
-	providerMap := map[string]string{
+	// 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",
+		"deepseek": "deepseek",
 		"xai":      "grok",
 	}
 
@@ -969,33 +972,35 @@ func (s *Server) handleGetModels(c *gin.Context) {
 		dbMap[m.ID] = m
 	}
 
-	// Fetch set of used model IDs if requested
-	usedModels := make(map[string]bool)
+	// Fetch specific (model, provider) combinations that have been used
+	type modelProvider struct {
+		Model    string `db:"model"`
+		Provider string `db:"provider"`
+	}
+	usedPairs := make(map[string]bool)
 	if usedOnly {
-		rows, err := s.database.Queryx("SELECT DISTINCT model FROM llm_requests")
+		var pairs []modelProvider
+		err := s.database.Select(&pairs, "SELECT DISTINCT model, provider FROM llm_requests WHERE status = 'success'")
 		if err == nil {
-			for rows.Next() {
-				var mID string
-				if err := rows.Scan(&mID); err == nil {
-					usedModels[mID] = true
+			for _, p := range pairs {
+				// Key format: "gpt-4o:openai"
+				usedPairs[fmt.Sprintf("%s:%s", p.Model, p.Provider)] = true
 			}
 		}
-			rows.Close()
-		}
 	}
 
 	var result []gin.H
 	if s.registry != nil {
 		for pID, pInfo := range s.registry.Providers {
-			// Normalize provider name for UI
-			uiProvider := pID
-			if mapped, ok := providerMap[pID]; ok {
-				uiProvider = mapped
+			// Only include models from the 4 allowed registry IDs
+			proxyProvider, allowed := allowedRegistryProviders[pID]
+			if !allowed {
+				continue
 			}
 
 			for mID, mMeta := range pInfo.Models {
-				// Filter if used_only requested
-				if usedOnly && !usedModels[mID] {
+				// If usedOnly is true, only include if this exact (model, provider) was logged
+				if usedOnly && !usedPairs[fmt.Sprintf("%s:%s", mID, proxyProvider)] {
 					continue
 				}
 
@@ -1038,7 +1043,7 @@ func (s *Server) handleGetModels(c *gin.Context) {
 				result = append(result, gin.H{
 					"id":               mID,
 					"name":             mMeta.Name,
-					"provider":         uiProvider,
+					"provider":         proxyProvider, // Correctly normalized provider name
 					"enabled":          enabled,
 					"prompt_cost":      promptCost,
 					"completion_cost":  completionCost,