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/groups/ExperimentalFeaturesPanel/ExperimentalFeaturesPanel.tsx

@@ -5,7 +5,6 @@ import {
   Button,
   Card,
   Checkbox,
-  CloseButton,
   Divider,
   Group,
   Stack,
@@ -15,6 +14,7 @@ import {
   Textarea,
   Title,
 } from "@mantine/core";
+import { ClearButton } from "../../elements/ClearButton/ClearButton";
 import type {
   ClientCapabilities,
   JSONRPCErrorResponse,
@@ -248,8 +248,7 @@ export function ExperimentalFeaturesPanel({
             rightSectionPointerEvents="auto"
             rightSection={
               header.key ? (
-                <CloseButton
-                  aria-label="Clear"
+                <ClearButton
                   onClick={() => onHeaderChange(index, "", header.value)}
                 />
               ) : null
@@ -264,8 +263,7 @@ export function ExperimentalFeaturesPanel({
             rightSectionPointerEvents="auto"
             rightSection={
               header.value ? (
-                <CloseButton
-                  aria-label="Clear"
+                <ClearButton
                   onClick={() => onHeaderChange(index, header.key, "")}
                 />
               ) : null
@@ -291,10 +289,7 @@ export function ExperimentalFeaturesPanel({
         rightSectionPointerEvents="auto"
         rightSection={
           requestDraft ? (
-            <CloseButton
-              aria-label="Clear"
-              onClick={() => onRequestChange("")}
-            />
+            <ClearButton onClick={() => onRequestChange("")} />
           ) : null
         }
       />