fix(web): section-header hover outline + clear buttons out of tab order (#1487) (#1488)

* fix(web): section-header hover outline + clear buttons out of tab order (#1487)

Two button-behavior adjustments:

1. History section headers (Pinned / History) now use the filter-toggle
   style — a thin outline on hover instead of a background fill — by pointing
   the `sectionHeader` Group variant at the shared `.filter-toggle` class. The
   open section keeps its filled background (passed per-instance via `bg`).

2. Every input clear button added in #1448 is removed from the keyboard tab
   order via `tabIndex={-1}` (CloseButton clear buttons app-wide, plus the
   Autocomplete clear button through `theme/Autocomplete.ts` clearButtonProps),
   so tabbing through a form moves to the next field, not onto the clear button.
   The buttons stay mouse-clickable.

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

* fix(web): apply filter-toggle hover outline to Resources accordion headers (#1487)

The Resources screen `disclosure` accordion controls now share the same
outline-on-hover treatment as the filter toggle buttons and History section
headers: a thin border on hover instead of a background fill, plus a filled
background when the section is open (keyed off `aria-expanded`). The `.filter-
toggle` class is added to the disclosure control slot; the default-variant
accordion (Server Settings) keeps its background-fill hover via a `:not(.filter-
toggle)` guard.

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

* refactor(web): extract ClearButton element, replace 34 inline clear buttons

Addresses the code-review suggestion on PR #1488: the same five-line
`CloseButton` clear-affordance block (aria-label="Clear" + tabIndex={-1} +
onClick) was hand-copied across 17 files. Extract a single
`elements/ClearButton` (Mantine `CloseButton.withProps` with the aria-label and
tabIndex baked in) and replace all 34 call sites, so the clear-button contract
lives in one place. A global CloseButton theme default would be wrong here — it
would also catch tabbable modal-close X buttons and the Select clear buttons —
so a dedicated element is the right altitude.

Net -151 lines. Adds element unit tests + a Storybook play test covering the
aria-label / tabIndex / clickable contract for all sites at once.

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

---------

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

clients/web/src/theme/Autocomplete.ts

@@ -8,5 +8,9 @@ export const ThemeAutocomplete = Autocomplete.extend({
     // collapses any open dropdown automatically. Per-site `clearable={false}`
     // can opt out where a clear button doesn't make sense.
     clearable: true,
+    // Keep the clear button out of the keyboard tab order so tabbing through a
+    // form moves to the next field, not onto the clear button (it stays
+    // mouse-clickable).
+    clearButtonProps: { tabIndex: -1 },
   },
 });