feat(files): the Downloads page goes — the tray, a Storage tab and a Downloads settings tab take its place

- The Downloads module, its rail icon and badge are gone. A bookmark, the remembered page and an old
  history entry that name it land on Files (urlState.resolvePage); `g d` goes to Files too.
- Users page: a Storage tab — the disk in numbers, every user's use against their own limit with
  their file count, every user's downloads; aligned tables, one menu per row (edit / reset quota,
  open source, copy, the owner's quota). The admin storage rows carry quota + file count, the admin
  job list its owner.
- Settings: a Downloads tab — the download formats in one list (duplicate a built-in, edit or delete
  your own) and the site sign-ins, moved from Account.
- "View" on an added download, a clip or a converting upload opens the tray on that row (unfolded,
  back if closed; a finished one opens as a file; under a player it opens without taking focus).
- The download dialog opens on the format used last.
- DataTable: `pager={false}` for a short list, `cardRow` to give a lone "…" its own card line.
- Welcome and README speak of Files; a new Files screenshot.

frontend/src/components/DownloadTray.tsx

@@ -18,12 +18,15 @@ import { failCopyKeys, failTitleKey } from "../lib/downloadFailure";
 import {
   IN_FLIGHT,
   clearFinished,
+  doneRevealing,
   fetchQueue,
   takeUnannounced,
   useFinished,
+  useRevealing,
   useUnannounced,
 } from "../lib/downloadQueue";
-import { navItemAttrs } from "../lib/listNav";
+import { anyBlockingLayer } from "../lib/layerStack";
+import { focusNavItem, navItemAttrs } from "../lib/listNav";
 import { notify } from "../lib/notifications";
 import { qk } from "../lib/queryKeys";
 import { LS } from "../lib/storage";
@@ -57,7 +60,8 @@ type Fold = "open" | "folded";
 const parseFold = (v: unknown): Fold => (v === "folded" ? "folded" : "open");
 const parseClosed = (v: unknown): string | null => (typeof v === "string" ? v : null);
 
-// Byte progress (a bar with a %) vs ffmpeg's post-steps (a pulse): the queue row's split.
+// Byte progress (a bar with a %) vs a post-step that reports none (a pulse): "editing" and
+// "converting" report a real % from ffmpeg's out_time.
 const BYTE_PHASES = ["video", "audio", "editing", "converting"];
 
 const keyOf = (job: QueueJob) => job.id;
@@ -132,6 +136,35 @@ export default function DownloadTray() {
     else if (target === "open") foldButton.current?.focus();
   }, [fold]);
 
+  // --- "View" on a job just started: the tray opens on its row ----------------------------------
+  // Answered over as many renders as it takes: a closed or folded tray is brought back first, and the
+  // row is focused once it is on the page. A job the tray does not list is done already (it opens as
+  // a file), or — once a poll made after the ask has landed without it — not in the queue at all.
+  // Asked from inside a player (a clip's notice, the player's own download), the tray opens under it
+  // but leaves the keyboard there: the row is behind the player, out of the reader's sight.
+  const box = useRef<HTMLDivElement>(null);
+  const revealing = useRevealing();
+  const answerReveal = useEffectEvent(() => {
+    if (!revealing) return;
+    const index = rows.findIndex((j) => j.id === revealing.id);
+    if (index >= 0) {
+      if (!shown) setClosedAt(null);
+      else if (fold === "folded") setFold("open");
+      else {
+        if (box.current && !anyBlockingLayer()) focusNavItem(box.current, index);
+        doneRevealing();
+      }
+      return;
+    }
+    const job = queueQ.data?.find((j) => j.id === revealing.id);
+    if (job?.status === "done") {
+      doneRevealing();
+      openFile(job.id, job.folder_id);
+    } else if (queueQ.dataUpdatedAt > revealing.at) doneRevealing();
+    else void qc.invalidateQueries({ queryKey: qk.downloads() });
+  });
+  useEffect(() => answerReveal(), [revealing, queueQ.data, shown, fold]);
+
   // --- the done notice ------------------------------------------------------------------------
   const announce = useEffectEvent((job: QueueJob) => {
     const title = jobTitle(job);
@@ -153,7 +186,6 @@ export default function DownloadTray() {
   }, [fresh]);
 
   // --- Back to top steps up over the tray while it shows -----------------------------------------
-  const box = useRef<HTMLDivElement>(null);
   useLayoutEffect(() => {
     const el = box.current;
     if (!el) {