refactor: enhance code clarity and maintainability across multiple files

- Updated comments to improve clarity and adhere to best practices in ascii.go, main.go, and diagnostics.
- Removed unnecessary linter directives for improved readability in imaging.go and ptz.go.
- Reformatted function signatures and added helper calls in tests for consistency and clarity.
- Enhanced error handling and logging consistency in various server files, ensuring better maintainability.

server/soap/handler_test.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 )
 
+const testXMLHeader = `<?xml version="1.0"?>`
 
 func TestNewHandler(t *testing.T) {
 	handler := NewHandler("admin", "password")
@@ -68,7 +69,7 @@ func TestServeHTTPValidSOAPRequest(t *testing.T) {
 	})
 
 	// Create SOAP request
-	soapBody := `<?xml version="1.0"?>
+	soapBody := testXMLHeader + `
 <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
   <soap:Body>
     <TestAction/>
@@ -323,7 +324,7 @@ func TestAuthenticateFailsWithWrongPassword(t *testing.T) {
 func TestHandlerWithoutAuthentication(t *testing.T) {
 	handler := NewHandler("", "") // No authentication
 
-	soapBody := `<?xml version="1.0"?>
+	soapBody := testXMLHeader + `
 <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
   <soap:Body>
     <TestAction/>