feat(modality): rename "file" modality label "Data" -> "Files"

The fifth user-facing group is now Image, Video, Audio, PDF, Files
(internal modality id stays "file"; section.ts "files" was already
"Files"). Updates modality.ts label + comment, all 21 i18n locales
(categories.data "Data Files"->"Files", modalities.documentsAndFiles
"PDF & Data"->"PDF & Files", dead homePage.data), landing cards/hero
search/tools filter, docs headings, and e2e modality-tab assertions
(/^Data/ -> /^Files/, which had been failing).

apps/landing/src/components/CategoryCards.astro

@@ -51,7 +51,7 @@ const MODALITIES = [
   {
     id: "file",
     section: "files",
-    label: "Data & Files",
+    label: "Files",
     blurb: "Convert and transform",
     icon: "Database",
     color: "#5C8642",

apps/landing/src/components/HeroSearch.astro

@@ -7,7 +7,7 @@ const MODALITY_META: Record<string, { label: string; color: string }> = {
   video: { label: "Video", color: "#BE4A3C" },
   audio: { label: "Audio", color: "#2C7A75" },
   document: { label: "PDF", color: "#44568C" },
-  file: { label: "Data", color: "#5C8642" },
+  file: { label: "Files", color: "#5C8642" },
 };
 
 function renderIcon(iconName: string): string {

apps/landing/src/pages/tools/index.astro

@@ -37,7 +37,7 @@ const modalityFilters = [
     label: "PDF & Docs",
     count: TOOLS.filter((t) => t.modality === "document").length,
   },
-  { id: "file", label: "Data", count: TOOLS.filter((t) => t.modality === "file").length },
+  { id: "file", label: "Files", count: TOOLS.filter((t) => t.modality === "file").length },
 ];
 
 const breadcrumbJsonLd = {