fix(phase-1): redact API key query params from log output and add mutex thread-safety to providers map

internal/server/providers_admin.go

@@ -82,7 +82,7 @@ func (s *Server) handleGetProviders(c *gin.Context) {
 
 		status := "disabled"
 		if enabled {
-			if _, ok := s.providers[id]; ok {
+			if _, ok := s.getProvider(id); ok {
 				status = "online"
 			} else {
 				status = "error"
@@ -203,7 +203,7 @@ func (s *Server) handleUpdateProvider(c *gin.Context) {
 
 func (s *Server) handleTestProvider(c *gin.Context) {
 	name := c.Param("name")
-	provider, ok := s.providers[name]
+	provider, ok := s.getProvider(name)
 	if !ok {
 		c.JSON(http.StatusNotFound, ErrorResponse(fmt.Sprintf("Provider %s not found or not enabled", name)))
 		return