Add prompt option to select fields in l_ui_form

[thomasgallagher]

Allows passing prompt: "Choose..." on :select field configs, shown as the first option and only selectable when no value is set. Suppresses the default blank option when set.

[claude]

Review

Adds a prompt: option for :select fields in l_ui_form, shown as the first (placeholder) option and only selectable when no value is set. When prompt: is provided, the default include_blank: true is suppressed.

Issues

Severity	File	Line(s)	Description
MEDIUM	app/helpers/layered/ui/form_helper.rb	37-38	prompt and include_blank are not excluded from the extras computation, so they land in extras and are deleted inside the :select branch - which is correct. However, if either key is accidentally passed on a non-select field type, they silently pass through as raw HTML attributes (e.g. prompt="foo" on a text input). This was already possible for any unknown key before this PR, but prompt is now a documented, user-facing option that increases the likelihood of this mistake. Consider adding :prompt and :include_blank to the exclusion list in form_helper.rb and reading them from config directly in _field_input.html.erb instead - consistent with how :collection and :placeholder are handled.

Verdict

🟧 Ship (with known minor issue) - Core logic is correct for the happy path; the extras-passthrough concern is a pre-existing pattern and the practical risk is low.

[claude]

Review of PR #87 - Add prompt option to select fields in l_ui_form

This PR adds a prompt: option to :select field configs in l_ui_form, and canonicalises include_blank: alongside it (previously extracted ad-hoc from extras in the partial).

The logic is correct throughout: include_blank defaults to true only when neither include_blank nor prompt is explicitly supplied; both are excluded from extras before the Rails select call so they cannot leak as HTML attributes; and the prior extras.delete(:include_blank) behaviour is preserved in effect. Documentation, changelog, and dummy-app examples are all consistent with the implementation.

✅ Ship