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/components/elements/ClearButton/ClearButton.tsx

@@ -0,0 +1,14 @@
+import { CloseButton } from "@mantine/core";
+
+/**
+ * The clear (×) affordance shown in a populated text input's right section
+ * (`rightSection`). Wraps Mantine's `CloseButton` with a fixed
+ * `aria-label="Clear"` and `tabIndex={-1}`, so the button stays mouse-clickable
+ * but is skipped during keyboard tab navigation — tabbing through a form lands
+ * on the next field, not on the clear button (see #1487). Pass `onClick` to
+ * reset the field's value to "". Both presets can still be overridden per-site.
+ */
+export const ClearButton = CloseButton.withProps({
+  "aria-label": "Clear",
+  tabIndex: -1,
+});