fix(web): unify MiniApp market typography and alignment

[bobleer]

Summary

The MiniApp submission workspace defined its own font sizes and paddings rather than reusing the gallery/form primitives, so the text read as ragged: section headings sat indented past the fields below them (the heading icon pushed title and description right by ~26px), hints rendered at three different sizes — several still inheriting the browser's 80% <small> default — and the textarea's box didn't match the inputs above and below it.

Everything in the view now follows one scale, each row borrowed from a component that already existed:

Role	Spec	Borrowed from
Section title	13px / 600 / primary	.gallery-zone__title
Section hint	12px / 400 / muted	.gallery-zone__subtitle
Field label	13px / 500 / secondary, 0.2px tracking	.bitfun-input-label
Field value	13px	.select__value
Inline hint	12px / muted	.bitfun-input-hint

Concretely:

• Alignment — section headings put the icon inline with the title, so title, description, labels, inputs, file rows, the advanced toggle and the submit button all share one left edge.
• Labels — Select/Input use their own label prop instead of hand-rolled <span> labels (which had a different colour, weight and gap), with one 6px label-to-control gap across the form.
• Textarea — now copies .bitfun-input-container's box (transparent background, --border-base, 12px inset, hover/focus ring) so the caret lines up with the single-line fields; Input (14px) and Select (13px) values are pinned to 13px within this view.
• Screenshot row — space-between across three children was pulling the two buttons apart; copy now sits left with the buttons grouped right (and "choose" gets a distinct icon from "capture").
• Measure — the form is capped at 620px instead of stretching single-line inputs across the full 1360px, with the history column pinned right.
• History icons — the submission list rendered the icon name as text (box) inside a 32px box; it now renders the icon via renderMiniAppIcon.

The market detail modal picks up the same title/body scale so the two tabs match.

No behaviour, i18n keys or API calls changed — markup structure, class names and styles only.

Testing

• npm run type-check clean
• eslint on the modified view clean
• Both SCSS files compile with sass
• Verified alignment by rendering the compiled stylesheets (plus the dark preset's theme variables) against a static copy of the form markup — the real app was not launched, so a visual pass in the Tauri app is still worth doing.