Mobile follow-ups to #7518: tool-list search, and drop the empty overflow menu (#7660)

# Description of Changes

Follow-up to #7518, picking up two mobile rough edges found while going
over that branch. Two changes, one commit each.

## 1. Tool search back in the tool list (mobile)

Tool search lives in the workbench bar's super search, which on mobile
sits on the Workspace slide. So searching for a tool meant swiping off
the tool list, typing, then swiping back. This puts a filter at the head
of the tool panel on mobile. Reuses the existing `ToolSearch` component
in `mode="filter"`, the same one the desktop fullscreen picker uses.
Drives `setSearchQuery` on `ToolWorkflowContext`, so the query,
filtering and grouped results are all existing paths. `ToolPanel` takes
a new `showSearch` prop; `RightSidebar` passes `showSearch={isMobile}`.
Desktop renders exactly as before.

**To test:**

- Open the editor at a phone-width viewport (under 1024px).
- A "Search tools..." field should sit above Favourites / Recommended in
the Tools pane.
- Typing filters into grouped results. Clearing goes back to the compact
list.
- It hides once a tool is open, and comes back on the way out.
- On desktop the field should not appear at all.

## 2. The mobile overflow menu opened with nothing in it

`WorkbenchBarMobileActions` rendered its kebab trigger unconditionally.
But every item inside is gated on `currentView === "viewer"` or
`!isCustomView`. In a `custom:*` workbench both are false, so the
dropdown was empty. `WorkbenchBarDesktopActions` renders nothing in that
case, so this only showed on phones. Now returns `null` when neither
group applies, with the two conditions named so the trigger and the
items can't drift apart again.

**To test:**

- Phone-width viewport, load a PDF.
- Open a tool with its own workbench view: Compare, Get Info report,
Show JS, Validate Signature, Edit Table of Contents, or PDF Text Editor.
- The kebab at the right of the workbench bar should be gone entirely,
rather than opening an empty menu.
- Back in the viewer or page editor it should still be there, with Print
/ Download / Save As / Close.

frontend/editor/src/core/components/shared/workbenchBar/WorkbenchBarMobileActions.tsx

@@ -25,6 +25,13 @@ export default function WorkbenchBarMobileActions({
 }: WorkbenchBarActionsProps) {
   const { t } = useTranslation();
   const exportDisabled = actionsDisabled || policyEnforcing;
+  const showPrint = currentView === "viewer";
+  const showFileActions = !isCustomView;
+
+  // Custom workbench views own their content, so none of these apply. The
+  // desktop cluster renders nothing at all in that case; without this the
+  // trigger would still be there, opening an empty dropdown.
+  if (!showPrint && !showFileActions) return null;
 
   return (
     <Menu shadow="md" width={230} position="bottom-end">
@@ -39,7 +46,7 @@ export default function WorkbenchBarMobileActions({
         </ActionIcon>
       </Menu.Target>
       <Menu.Dropdown>
-        {currentView === "viewer" && (
+        {showPrint && (
           <Menu.Item
             leftSection={<PrintIcon sx={{ fontSize: "1.1rem" }} />}
             disabled={exportDisabled}
@@ -48,7 +55,7 @@ export default function WorkbenchBarMobileActions({
             {t("workbenchBar.print", "Print PDF")}
           </Menu.Item>
         )}
-        {!isCustomView && (
+        {showFileActions && (
           <Menu.Item
             leftSection={
               <LocalIcon
@@ -63,7 +70,7 @@ export default function WorkbenchBarMobileActions({
             {downloadLabel}
           </Menu.Item>
         )}
-        {!isCustomView && saveAsIconName && (
+        {showFileActions && saveAsIconName && (
           <Menu.Item
             leftSection={
               <LocalIcon icon={saveAsIconName} width="1.1rem" height="1.1rem" />
@@ -74,7 +81,7 @@ export default function WorkbenchBarMobileActions({
             {t("workbenchBar.saveAs", "Save As")}
           </Menu.Item>
         )}
-        {!isCustomView && (
+        {showFileActions && (
           <>
             <Menu.Divider />
             <Menu.Item

frontend/editor/src/core/components/tools/RightSidebar.tsx

@@ -282,6 +282,9 @@ export default function RightSidebar() {
               onShowAllTools={handleShowAllTools}
               onToolSelect={handleToolSelectWithTransition}
               compact={false}
+              /* Mobile keeps the workbench bar - and with it the super search -
+                 on the other slide, so the list needs its own filter. */
+              showSearch={isMobile}
             />
           </>
         </div>

frontend/editor/src/core/components/tools/ToolPanel.css

@@ -183,6 +183,17 @@
   }
 }
 
+/* In-panel tool filter. Aligned with .tool-picker__compact's inline padding so
+   the field lines up with the tool rows underneath it. */
+.tool-panel__search {
+  flex-shrink: 0;
+  padding: 0.5rem var(--mantine-spacing-sm) 0;
+}
+
+.tool-panel__search .search-input-container {
+  margin: 0;
+}
+
 .tool-panel__compact-header-actions {
   display: flex;
   align-items: center;

frontend/editor/src/core/components/tools/ToolPanel.tsx

@@ -4,6 +4,7 @@ import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
 import ToolPicker from "@app/components/tools/ToolPicker";
 import SearchResults from "@app/components/tools/SearchResults";
 import ToolRenderer from "@app/components/tools/ToolRenderer";
+import ToolSearch from "@app/components/tools/toolPicker/ToolSearch";
 import { ToolPanelViewerBar } from "@app/components/tools/ToolPanelViewerBar";
 import { ToolId } from "@app/types/toolId";
 
@@ -20,6 +21,11 @@ interface ToolPanelProps {
   onToolSelect?: (id: ToolId) => void;
   /** Whether to render the compact (favourites + recommended only) view. */
   compact?: boolean;
+  /**
+   * Render a tool filter at the head of the panel. Set where the workbench
+   * bar's super search is out of reach, so the list stays searchable in place.
+   */
+  showSearch?: boolean;
 }
 
 /** Tool list and renderer for the right rail; rail chrome lives in RightSidebar. */
@@ -28,24 +34,44 @@ export default function ToolPanel({
   onShowAllTools,
   onToolSelect,
   compact: compactProp,
+  showSearch = false,
 }: ToolPanelProps) {
   const { t } = useTranslation();
   const {
     leftPanelView,
     searchQuery,
+    setSearchQuery,
     filteredTools,
+    toolRegistry,
     selectedToolKey,
     handleToolSelect,
     setPreviewFile,
   } = useToolWorkflow();
   const selectTool = onToolSelect ?? handleToolSelect;
 
+  // Only offer the filter over the list itself; once a tool is open the panel
+  // belongs to that tool. Deriving the results branch from the same flag keeps
+  // the input and what it filters from drifting apart.
+  const panelSearch = showSearch && leftPanelView === "toolPicker";
+  const searching = searchQuery.trim().length > 0;
+
   return (
     <>
       {/* Viewer mode tools — annotate, redact, form fill */}
       <ToolPanelViewerBar />
 
-      {allToolsView && searchQuery.trim().length > 0 ? (
+      {panelSearch && (
+        <div className="tool-panel__search">
+          <ToolSearch
+            value={searchQuery}
+            onChange={setSearchQuery}
+            toolRegistry={toolRegistry}
+            mode="filter"
+          />
+        </div>
+      )}
+
+      {searching && (allToolsView || panelSearch) ? (
         <div className="flex-1 flex flex-col overflow-y-auto">
           <SearchResults
             filteredTools={filteredTools}
@@ -59,7 +85,7 @@ export default function ToolPanel({
             selectedToolKey={selectedToolKey}
             onSelect={(id) => selectTool(id as ToolId)}
             filteredTools={filteredTools}
-            isSearching={Boolean(searchQuery && searchQuery.trim().length > 0)}
+            isSearching={searching}
             compact={compactProp ?? !allToolsView}
             onShowAllTools={onShowAllTools}
           />