fix: eradicate tailwind @apply usage in vue styles (#9146)

## Summary

Remove Tailwind `@apply` from Vue styles across `src/` and
`apps/desktop-ui/src/` to align with Tailwind v4 guidance, replacing
usages with template utilities or native CSS while preserving behavior.

## Changes

- **What**:
- Batch 1: migrated low-risk template/style utility bundles out of
`@apply`.
- Batch 2: converted PrimeVue/`:deep()` override `@apply` blocks to
native CSS declarations.
- Batch 3: converted `src/components/node/NodeHelpContent.vue` markdown
styling from `@apply` to native CSS/token-based declarations.
- Batch 4: converted final desktop pseudo-element `@apply` styles and
removed stale `@reference` directives no longer required.
- Verified `rg -n "^\s*@apply\b" src apps -g "*.vue"` has no real CSS
`@apply` directives remaining (only known template false-positive event
binding in `NodeSearchContent.vue`).

## Review Focus

- Visual parity in components that previously depended on `@apply` in
`:deep()` selectors and markdown content:
  - topbar tabs/popovers, dialogs, breadcrumb, terminal overrides
  - desktop install/dialog/update/maintenance surfaces
  - node help markdown rendering
- Confirm no regressions from removal of now-unneeded `@reference`
directives.

## Screenshots (if applicable)

- No new screenshots included in this PR.
- Screenshot Playwright suite was run with `--grep="@screenshot"` and
reports baseline diffs in this environment (164 passed, 39 failed, 3
skipped) plus a teardown `EPERM` restore error on local path
`C:\Users\DrJKL\ComfyUI\LTXV\user`.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9146-fix-eradicate-tailwind-apply-usage-in-vue-styles-3116d73d3650813d8642e0bada13df32)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/components/bottomPanel/tabs/terminal/BaseTerminal.vue

@@ -103,13 +103,12 @@ onUnmounted(() => {
 </script>
 
 <style scoped>
-@reference '../../../../assets/css/style.css';
-
 :deep(.p-terminal) .xterm {
-  @apply overflow-hidden;
+  overflow: hidden;
 }
 
 :deep(.p-terminal) .xterm-screen {
-  @apply bg-neutral-900 overflow-hidden;
+  overflow: hidden;
+  background-color: var(--color-neutral-900);
 }
 </style>