Audit all `mt-tabs` UI paths with `V6_8_0_0` enabled

### Technical TODO

## Context

Updating Meteor changes `mt-tabs` attribute forwarding. Classes placed on the Shopware wrapper now reach Meteor’s rendered `.mt-tabs` element.

That can restore intended styling, but it can also reactivate CSS that was effectively inactive before. We need a systematic visual audit of every Administration surface that renders `mt-tabs` on the 6.8 feature path.

Initial comparisons are documented in [PR #19607](https://github.com/shopware/shopware/pull/19607#issuecomment-5453366303). The checked examples are:

- Product media modal
- Media folder settings
- Flow Builder
- Settings → Search → Searchable content

## Goal

Verify that all 6.8-gated `mt-tabs` usages look correct and remain consistent with the intended 6.7 layout where applicable.

## Scope

1. Run the Administration with `FEATURE_ALL=major` / `V6_8_0_0` enabled.
2. Inventory every rendered `` usage in Administration, including modal, detail-page, CMS, Settings, Flow Builder, Order, Product, Customer, Sales Channel, and profile surfaces.
3. For each surface:
- Compare against the 6.7 path or the intended design.
- Check tab spacing, width, alignment, padding, background, active state, and surrounding content spacing.
- Inspect whether consumer classes are now present on the rendered `.mt-tabs` element.
- Pay particular attention to CSS selectors that target wrapper-specific classes.
4. Record screenshots or concise findings for every regression found.
5. Create focused follow-up issues for confirmed regressions; do not change unrelated styles as part of this audit.

## Acceptance criteria

- Every Administration `` surface reachable with `V6_8_0_0` enabled has been reviewed.
- The four initially checked surfaces are revalidated against the documented comparisons.
- Confirmed visual regressions have a reproducible route, screenshot, expected result, and dedicated follow-up issue.
- The audit distinguishes intentional Meteor visual differences from regressions caused by newly forwarded classes.

Start by running the Administration with FEATURE_ALL=major and V6_8_0_0 enabled, then inventory every rendered surface. Revalidate the four examples documented in PR #19607 and inspect spacing, alignment, active states, surrounding content, and forwarded wrapper classes. Done means every reachable surface is reviewed, findings or screenshots are recorded, and confirmed regressions have reproducible routes and follow-up issues.

Written by the indexing model from the issue text.