[chubes4]

Part of Automattic/static-site-importer#2071. Stacked on #2785.

Problem

A submit whose caption is painted by a block-level inner carrier (<a class="btn"><span class="inner">Send</span></a>, <button><span>) takes its box from that carrier: the button declares padding:0 and the span carries padding:.625em 1.9375em and text-transform. Providers render the caption directly into one button element, so the source carried only color and font properties and the button lost its padding (27px vs the source's 44px) and case.

Consumers take the submit box from this graph (Automattic/static-site-importer#2085 makes the resolved graph authoritative over the per-control style).

Change

• A button caption carrier (the sole text carrier of a button, or of the element painting an off-screen submit from fix: describe the element that paints an off-screen native submit #2785) now carries text-transform with its typography.
• A block-level carrier also carries its padding when the button box is unpadded. Inline carriers and padded buttons keep the button's own box.

Evidence

• New tests/unit/form-submit-caption-box.php (6 assertions): block/inline carriers, padded button, and a responsive carrier variant. 4 fail on trunk; all pass here.
• The form/button/label unit tests pass locally.
• Hosted-builder contact page (offline harness with static-site-importer#2085): the submit overlay now carries padding:0.625em 1.9375em, text-transform:uppercase, text-decoration:none. Before, it carried padding:0 and no case.

AI disclosure: implemented with Claude (Pi backend via Roadie); Claude traced the seeder precedence, wrote the change and tests, and ran the verification.