Add pleaseChoose option to SelectElement

[jrauh01]

Add a pleaseChoose option to SelectElement that prepends the placeholder automatically:

(new SelectElement('type'))
    ->setOptions($types)
    ->setPleaseChoose(true);

Or declaratively:

[
    'type'         => 'select',
    'options'      => $types,
    'pleaseChoose' => true,
]

When enabled and no '' option does exist, the element prepends ['' => sprintf(' - %s - ', t('Please choose'))] to the rendered options and marks it as disabled, so callers do not need to handle either step.

resolve #199

[Copilot]

Pull request overview

Adds a pleaseChoose option to SelectElement that lazily prepends a disabled '' placeholder option (" - Please choose - ") at assembly time, both via a fluent setter and a declarative attribute. The change centralizes a repeated pattern previously duplicated across forms (issue #199).

Changes:

• New pleaseChoose property with setPleaseChoose() setter.
• assemble() prepends a disabled SelectOption with empty value when pleaseChoose is enabled and no top-level '' option already exists; selection callback reuses isSelectedOption('').
• Registers a pleaseChoose declarative attribute setter callback (matching the first-class-callable style already used elsewhere) and adds four tests covering rendering, value-selection, non-override, and lazy fluent API behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/FormElement/SelectElement.php	Adds $pleaseChoose flag, setter, assembly-time placeholder injection, and declarative attribute callback.
tests/FormElement/SelectElementTest.php	Adds four tests covering prepend rendering, deselection when a value is set, no-override of existing empty option, and lazy fluent-API behavior.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.