fix: various visual component fixes + floating-ui/colorpicker positioning (#1255)

* fix: mt-action-menu z-index order

* fix: mt-banner adjust close icon and typo spacing

* fix: adjust gap of checkbox and switch, plus added gap to mt-base-field label

* fix: adjust checkbox component icon, spacing and default line-height and font-size for mt-base-field labels

* fix: select field icons, spacing, active state etc.

* fix: select and button changes

* fix: keep mt-colorpicker popover absolutely positioned

The floating-ui root carries both .mt-floating-ui (position: relative) and
.mt-colorpicker__colorpicker-position (position: absolute). Both are plain,
equal-specificity class selectors in unscoped stylesheets, so the winner
depended on bundle source order — intermittently letting .mt-floating-ui win
and dropping the closed popover back into document flow.

Qualify the rule with the .mt-colorpicker ancestor so it deterministically
wins, mirroring the existing --compact rule. Removes the need for a :deep
override in consuming code.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix: pin mt-floating-ui content position to the computed strategy

The teleported .mt-floating-ui__content is positioned by writing the
floating-ui coordinates inline, but `position` was left to CSS. Consumer
classes passed on <mt-floating-ui class="..."> are copied onto this element,
so a class carrying `position: absolute` (e.g. mt-colorpicker's positioning
class) flipped the fixed-strategy coordinates into document space — the
popover then rendered in a seemingly random spot and drifted away on scroll.

Write `position: strategy` inline alongside top/left so it always matches the
coordinate space floating-ui computed for. Inline style wins over any copied
class, immunizing every consumer against this class of misposition.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* chore: add changeset for visual component fixes

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* chore: remove commented-out CSS in mt-label and mt-select-selection-list

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix: update icon references after mt-checkbox icon rename

The checkbox check/partial icons changed from regular-checkmark-xxs /
regular-minus-xxs to solid-checkmark-xs / solid-minus-xs. Update the
references that still pointed at the old names:

- mt-popover-item spec assertions (was failing in CI)
- mt-checkbox interactive story assertion
- mt-segmented-control checkmark sizing selector (was silently no longer
  matching)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* update snapshots

* fix: redesign number field stepper and align radio group spacing

- mt-number-field: the increment/decrement controls become a bordered
  box (1px border, --border-radius-xs) split 50/50 by a 1px separator,
  icons centered, 32px wide, height matched to the field in every size
- mt-unit-field: inherits the stepper box from the number field, drops
  the doubled gap toward the unit select trigger, and hides the stepper
  via a container query below 240px
- mt-radio-group-item: indicator-to-label gap 4px -> 8px, matching the
  earlier checkbox and switch spacing adjustment

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* update snapshots

* fix: correct field visual regressions from spacing and icon changes

- mt-checkbox: restore centered box alignment by default; gate the
  first-line offset (margin-top) behind the new consistentLabelLineHeight
  future flag and a has-label check, so label-less checkboxes (data
  tables, custom layouts) are no longer pushed down
- mt-checkbox: bordered variant gets min-height like the switch instead
  of relying on vertical padding, fixing its height
- mt-base-field: label line-height stays the legacy 16px by default; the
  token line-height (--font-line-height-xs) is opt-in via
  consistentLabelLineHeight so existing label baselines are preserved
- mt-segmented-control: checkbox keeps no first-line offset (the action
  centers its content itself)
- mt-modal: center the close button icon (a bare button does not, so the
  inline-block icon sat low on the baseline)
- mt-number-field: add a disabled state for the stepper box; hide the
  stepper via a container query when the field is too narrow (e.g. the
  number fields inside a range slider), moved off mt-unit-field so it
  applies to plain number fields and sliders too

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* update snapshots

* chore: drop the code comments added with the field fixes

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Adjusted icon sizes in input components

* update snapshots

* Adjusted icon sizes in input components

* test: drop full-page screenshot assertion from nuxt-app smoke test

Keeps the functional smoke checks; whole-page pixel regression is
redundant with the component library's own visual snapshots and broke
on every component restyle.

* update snapshots

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: arnoldstoba

.changeset/visual-component-fixes.md

@@ -27,6 +27,4 @@ test('renders an example page', async ({ page }) => {
   await inputField.fill('Hello, World!');
 
   await expect(text).toHaveText('Hello, World!');
-
-  await expect(page).toHaveScreenshot();
 });