Downgrade engine default message to trace level (#3687)

* Initial plan

* Downgrade engine default message to trace level

Change the message "No 'engine:' setting found, defaulting to: copilot"
from an info-level message (displayed with --verbose flag) to a trace-level
message (displayed only when DEBUG=workflow:compiler or DEBUG=* is set).

This reduces noise in verbose output while still making the information
available for debugging purposes.

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Author: Copilot

pkg/workflow/compiler.go

@@ -710,9 +710,7 @@ func (c *Compiler) ParseWorkflowFile(markdownPath string) (*WorkflowData, error)
 	if engineSetting == "" {
 		defaultEngine := c.engineRegistry.GetDefaultEngine()
 		engineSetting = defaultEngine.GetID()
-		if c.verbose {
-			fmt.Println(console.FormatInfoMessage(fmt.Sprintf("NOTE: No 'engine:' setting found, defaulting to: %s", engineSetting)))
-		}
+		log.Printf("No 'engine:' setting found, defaulting to: %s", engineSetting)
 		// Create a default EngineConfig with the default engine ID if not already set
 		if engineConfig == nil {
 			engineConfig = &EngineConfig{ID: engineSetting}