feat(design): the field family, the dropdown trigger, native controls, the no-raw-input lint rule (E28 S3c)

- ui/Input, Textarea, InnerInput + fieldClass (A4): the >= 3:1 edge, a 2px accent
  focus edge, the danger edge for invalid, md/sm/xs/heading rungs, 1rem and 44 on touch
- ui/SelectTrigger (A5): SortControl, FilterSelect, the view switcher and the date
  filter on one trigger, a pill in a toolbar, r8 in a form
- ui/NativeControls (A6): Checkbox, CheckRow, Slider, ColorInput
- every raw input swept (~100 sites); inputCls retired; local/input-primitive
- useReturnFocus: an in-place editor hands the focus back to its trigger on
  Enter/Escape (the playlist and Plex title renames, the priority number);
  the Plex playlist rename gains Escape and an accessible name
- back to top: a round 48 FAB (owner decision); DESIGN.md A2 and the log

frontend/src/components/UploadDialog.tsx

@@ -13,8 +13,8 @@ import { notify } from "../lib/notifications";
 import { navigateTo } from "../lib/nav";
 import { formatBytes } from "../lib/format";
 import { DISPLAY_NAME_MAX } from "../lib/api/downloads";
-import { inputCls } from "./ui/form";
 import { Pressable } from "./ui/Pressable";
+import { Input } from "./ui/Input";
 
 // Local-file ingest (E7 S5c · D5-A). A general upload — ANY file type, no format list: media
 // (video/audio) joins the library with the full function set, a generic file is download-only. The
@@ -179,7 +179,8 @@ export default function UploadDialog({ onClose }: { onClose: () => void }) {
       <label htmlFor="upload-display-name" className="block text-sm font-medium mt-4 mb-1">
         {t("downloads.upload.nameLabel")}
       </label>
-      <input
+      <Input
+        className="w-full mb-5"
         id="upload-display-name"
         value={name}
         onChange={(e) => setName(e.target.value)}
@@ -190,7 +191,6 @@ export default function UploadDialog({ onClose }: { onClose: () => void }) {
         // third copy: `downloads.contract.test.ts` holds DISPLAY_NAME_MAX against the backend's
         // own DISPLAY_TEXT_MAX.
         maxLength={DISPLAY_NAME_MAX}
-        className={`${inputCls} mb-5`}
       />
 
       {busy && (