Clean up debug output from logging investigation

- Removed temporary debug prints from config loading
- Removed temporary debug prints from logger initialization
- Removed temporary debug prints from main.go
- Logging fix complete: config/local.yaml updated locally
- Bot now properly writes logs to logs/mev-bot.log file

Note: local.yaml changes not committed (ignored by .gitignore)
Users should update their local config files manually

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/logger/logger.go

@@ -18,9 +18,11 @@ func New(level string, format string, file string) *Logger {
 	if file != "" {
 		f, err := os.OpenFile(file, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
 		if err != nil {
-			log.Fatal(err)
+			log.Printf("Failed to create log file %s: %v, falling back to stdout", file, err)
+			output = os.Stdout
+		} else {
+			output = f
 		}
-		output = f
 	} else {
 		output = os.Stdout
 	}