fix(files): review round 1, the page — honest states, the keyboard, the tray's words

- A library past the list's cap is searched and sorted on the server; the count says "the newest".
- Each folder and each search opens on its first page (DataTable pageScope, useCardPager scope).
- A file dropped where the page takes none never reaches the browser (which would unload the app).
- The viewer's arrows wait while a layer opened from it is on top, and scroll a wide text line;
  a text shows its first 5000 lines and says where the rest is.
- Confirms name the file (no more "your downloads"); the asking menu rows end in "…".
- The tray names a running step beside its bar, shows a pause mark for paused work, polls slowly
  while only paused work waits, and forgets a finished file that was deleted.
- An unchanged rename sends nothing; a paste opens the download dialog only with nothing on top;
  the link box never replaces what was typed.
- Honest states: folders that failed to load, a file no longer there, the storage figure; the rail
  says "nothing downloaded" only when there is nothing.
- Focus after deleting the open folder and when the format form opens; the format name's label.
- ui/Meter (one danger line for both quota bars) and ui/RenameField in the platform layer.
- Copy fixes, stale comments and the speculative hub key; a contract test for the list's
  parameters; e2e: the Files page and the paste intake.

frontend/src/components/ProfileEditor.dom.test.tsx

@@ -111,7 +111,9 @@ describe("DownloadFormats", () => {
     await mount();
     await openMenu(rowOf("Phone 480"));
     pick("downloads.profiles.duplicate");
-    const name = await screen.findByPlaceholderText("downloads.profiles.namePlaceholder");
+    // The form opens with the keyboard in its name, the field named by its label.
+    const name = await screen.findByRole("textbox", { name: "downloads.profiles.name" });
+    await waitFor(() => expect(document.activeElement).toBe(name));
     expect((name as HTMLInputElement).value).toBe("");
     fireEvent.change(name, { target: { value: "Phone copy" } });
     fireEvent.click(screen.getByText("downloads.profiles.create"));