feat(files): add a name filter to My Files with a no-results state

Reconnects the existing (orphaned) name-filter pipeline with an input next
to the sort controls. When a filter returns nothing, the page shows a
dedicated 'no matching files' empty state instead of the generic per-tab
message (e.g. 'Nothing modified yet').

frontend/editor/src/core/components/filesPage/FileGrid.tsx

@@ -13,6 +13,7 @@ import DriveFileRenameOutlineIcon from "@mui/icons-material/DriveFileRenameOutli
 import CloudUploadIcon from "@mui/icons-material/CloudUpload";
 import UploadFileIcon from "@mui/icons-material/UploadFile";
 import CreateNewFolderIcon from "@mui/icons-material/CreateNewFolder";
+import SearchIcon from "@mui/icons-material/Search";
 
 import { FileId } from "@app/types/file";
 import { FolderId, FolderRecord, ROOT_FOLDER_ID } from "@app/types/folder";
@@ -85,6 +86,8 @@ interface FileGridProps {
   onChangeSortMode?: (mode: FilesPageSortMode) => void;
   /** Drives the empty-state copy. */
   currentTab?: "all" | "local" | "cloud" | "recent" | "shared" | "sharedByMe";
+  /** A filter is applied; an empty result then means "no matches", not "no files". */
+  searchActive?: boolean;
   /** Cloud reachability; switches the cloud empty-state copy. */
   serverReachable?: boolean;
   /** Empty-state CTA handlers; if absent the matching button hides. */
@@ -100,6 +103,7 @@ export function FileGrid(props: FileGridProps & { loading?: boolean }) {
     entries,
     loading,
     currentTab,
+    searchActive,
     serverReachable,
     onEmptyUpload,
     onEmptyCreateFolder,
@@ -114,6 +118,7 @@ export function FileGrid(props: FileGridProps & { loading?: boolean }) {
     return (
       <EmptyState
         tab={currentTab}
+        searchActive={searchActive}
         serverReachable={serverReachable}
         onUpload={onEmptyUpload}
         onCreateFolder={onEmptyCreateFolder}
@@ -183,6 +188,8 @@ function SkeletonGrid({ viewMode }: { viewMode: FilesPageViewMode }) {
 interface EmptyStateProps {
   /** Drives copy + iconography. */
   tab?: "all" | "local" | "cloud" | "recent" | "shared" | "sharedByMe";
+  /** When true the empty list is the result of a filter, not a bare folder. */
+  searchActive?: boolean;
   /** Switches the cloud empty-state copy. */
   serverReachable?: boolean;
   /** CTA handlers; absent => button hidden. */
@@ -194,12 +201,35 @@ interface EmptyStateProps {
 
 function EmptyState({
   tab = "all",
+  searchActive = false,
   serverReachable = true,
   onUpload,
   onCreateFolder,
   newFolderDisabledReason,
 }: EmptyStateProps) {
   const { t } = useTranslation();
+
+  // A filter with no matches isn't an empty folder - say so, and skip the
+  // upload / new-folder CTAs since clearing the filter is the way out.
+  if (searchActive) {
+    return (
+      <div className="files-page-empty">
+        <span className="files-page-empty-icon">
+          <SearchIcon style={{ fontSize: "2.5rem" }} />
+        </span>
+        <div className="files-page-empty-title">
+          {t("filesPage.empty.noResults.title", "No matching files")}
+        </div>
+        <div className="files-page-empty-hint">
+          {t(
+            "filesPage.empty.noResults.hint",
+            "No files in this folder match your filter. Try a different term or clear the filter.",
+          )}
+        </div>
+      </div>
+    );
+  }
+
   const { titleKey, titleFallback, hintKey, hintFallback } = (() => {
     switch (tab) {
       case "local":

frontend/editor/src/core/components/filesPage/FileManagerView.tsx

@@ -15,10 +15,12 @@ import {
   MultiSelect,
   SegmentedControl,
   Select,
+  TextInput,
   Tooltip,
 } from "@mantine/core";
 import { useMediaQuery } from "@mantine/hooks";
 import CloseIcon from "@mui/icons-material/Close";
+import SearchIcon from "@mui/icons-material/Search";
 import UploadFileIcon from "@mui/icons-material/UploadFile";
 import QrCode2Icon from "@mui/icons-material/QrCode2";
 import CreateNewFolderIcon from "@mui/icons-material/CreateNewFolder";
@@ -136,6 +138,7 @@ export default function FileManagerView() {
     sortMode,
     setSortMode,
     search,
+    setSearch,
     originFilter,
     setOriginFilter,
     typeFilter,
@@ -1360,6 +1363,30 @@ export default function FileManagerView() {
                   aria-label={t("filesPage.typeFilter.label", "Filter by type")}
                 />
               )}
+              <TextInput
+                size="xs"
+                value={search}
+                onChange={(e) => setSearch(e.currentTarget.value)}
+                placeholder={t("filesPage.search.placeholder", "Filter files…")}
+                leftSection={<SearchIcon sx={{ fontSize: "1rem" }} />}
+                rightSection={
+                  search ? (
+                    <ActionIcon
+                      variant="subtle"
+                      size="sm"
+                      onClick={() => setSearch("")}
+                      aria-label={t("filesPage.search.clear", "Clear filter")}
+                    >
+                      <CloseIcon sx={{ fontSize: "0.9rem" }} />
+                    </ActionIcon>
+                  ) : null
+                }
+                aria-label={t(
+                  "filesPage.search.label",
+                  "Filter files by name",
+                )}
+                style={{ width: 180 }}
+              />
               <Select
                 size="xs"
                 value={sortMode}
@@ -1451,6 +1478,7 @@ export default function FileManagerView() {
               entries={entries}
               loading={loading}
               currentTab={currentTab}
+              searchActive={search.trim().length > 0}
               serverReachable={folders.serverReachable}
               selectedFileIds={selectedFileIds}
               activeWorkspaceFileIds={activeWorkspaceFileIdSet}