Why the group container gained a native title/desc instead of a leading html option

The question: Can the group container type carry a label of its own, so we stop faking section headings with a leading html option?

Context

Reorganising the Header Layout and Mobile & Tablet tabs into type => 'group' boxes gave us ~19 groups. Each group needed a visible heading (and one needed a short note — "a different mobile logo lives under Identity"). The framework's group container had no title concept, so every group led with a throwaday html option:

'grp_toggle' => [
    'type'    => 'group',
    'options' => [
        'toggle_heading' => [ 'type' => 'html', 'label' => false, 'html' => '<h4 …>Hamburger / Toggle</h4>' ],
        // …real options…
    ],
],

That works, but it's wrong on three counts: the heading is a fake option occupying an id in a data array; its markup/inline-styles are duplicated at every call site; and the label lives inside options rather than as an attribute of the group, so grouping and labelling are two disconnected ideas.

Options considered

• Keep the leading html option. Zero framework change, but the noise multiplies with every group and the styling drifts (each site/tab re-invents the <h4 style=…>).
• A helper closure ($heading() / $section()) per options file. Removes the copy-paste but still emits a fake option, still per-file, still not an attribute of the group.
• Native title (+ desc) on the group container, rendered only when set. One place owns the markup; the label becomes an attribute of the thing it labels; every group across the plugin benefits.

Decision

Add optional title and desc parameters to FW_Container_Type_Group::_render(). title renders as a small uppercase "eyebrow" section label — deliberately a muted <div class="fw-backend-options-group__title">, not a content <h4>, so it marks a section without competing with the field labels beneath it; desc allows limited inline HTML (wp_kses_post) in a muted <p class="fw-backend-options-group__desc">. Both render only when present, so every existing group in the plugin is untouched. The Header Layout and Mobile & Tablet tabs were then refactored to use title/desc and drop their html heading options (the "mobile logo" note became the Layout group's desc).

Why

• Back-compat is free — an unset title/desc renders nothing, so the thousands of existing groups are byte-identical in output.
• One owner for the markup — the box heading style lives in the container renderer, not scattered inline styles across option files, so it stays consistent and themeable via two real classes.
• The model reads right — a group's label is now an attribute of the group, mirroring how box/tab already carry a title. Grouping and labelling are one construct, which is exactly what a reader skimming the option array expects.

The options-framework docs (/docs/options) were updated to document the two new parameters.