feat(files): download from anywhere — a link box, a pasted link, the palette; the running downloads in a tray

- Files toolbar link box (paste button, Enter); a lone http(s) link pasted onto any page opens the one
  app-wide download dialog, which now names the link; the palette's "Download from a link…" focuses
  the box on its history entry.
- The download tray, bottom right on every page: what waits, runs, is paused or failed (reason +
  Retry, the queue's right-click / "…" menu), and what finished in this tab as "Done · Open" until
  closed; folds to a pill (per-account pref); closed, it stays shut — across a reload — until the
  work changes or something finishes. Back to top steps up over it, the page end keeps clear.
- A finish is announced once: "Downloaded: …", whether a phone plays it, Copy link + Open (toasts
  and notices may carry a second action).
- The inbox's ready notice opens the file in its folder: download_done carries job_id + folder_id.
- GET /api/downloads is the queue only (in flight, failed, finished in the last 10 minutes), with
  each row's source key.

frontend/src/components/NotificationsPanel.tsx

@@ -8,9 +8,9 @@ import {
   Bell,
   Check,
   CheckCheck,
-  Download,
   ExternalLink,
   Eye,
+  FolderOpen,
   RotateCcw,
   Search,
   Trash2,
@@ -45,6 +45,7 @@ import { PageToolbar } from "./ui/PageShell";
 import { PageMenu } from "./ui/PageMenu";
 import { LoadingState, StateMessage } from "./ui/QueryState";
 import { useNavigationActions } from "./navigationContext";
+import { useFilesActions } from "./filesContext";
 import { useChannelsActions } from "./channelsContext";
 import { useFeedFilters, useFeedFiltersActions } from "./feedFiltersContext";
 import { SURFACE } from "./ui/surfaces";
@@ -71,6 +72,7 @@ const byId = (n: { id: number }) => n.id;
 export default function NotificationsPanel() {
   const { t } = useTranslation();
   const { setPage } = useNavigationActions();
+  const { openFile } = useFilesActions();
   const filters = useFeedFilters();
   const { setFilters } = useFeedFiltersActions();
   // "Focus this channel in the manager" (from a new-subscription notification) lives in
@@ -184,7 +186,12 @@ export default function NotificationsPanel() {
   const serverMenu = useContextMenu<AppNotification>({ keyOf: byId });
   const clientMenu = useContextMenu<ClientNotif>({ keyOf: byId });
   const openScheduler = () => setPage("scheduler");
-  const openDownloads = () => setPage("downloads");
+  // A finished download opens on its file, in its folder; a notice from before it named one, on Files.
+  const openDone = (n: AppNotification) => {
+    const { job_id: id, folder_id: folder } = n.data ?? {};
+    if (typeof id === "number") openFile(id, typeof folder === "number" ? folder : null);
+    else setPage("files");
+  };
   const reviewAccess = () => {
     focusAccessRequestsTab();
     setPage("users");
@@ -213,9 +220,9 @@ export default function NotificationsPanel() {
             ? [
                 {
                   id: "open",
-                  label: t("inbox.openDownloads"),
-                  icon: icon(Download),
-                  onSelect: openDownloads,
+                  label: t("inbox.openFile"),
+                  icon: icon(FolderOpen),
+                  onSelect: () => openDone(n),
                 },
               ]
             : []),
@@ -280,17 +287,15 @@ export default function NotificationsPanel() {
                   onSelect: reviewAccess,
                 },
               ]
-            : n.action && !n.dismissed
-              ? [
-                  {
-                    id: "action",
-                    label: n.action.label,
-                    onSelect: () => {
-                      n.action!.onClick();
-                      dismissClient(n.id);
-                    },
+            : !n.dismissed
+              ? liveActions(n).map((action, i) => ({
+                  id: `action${i}`,
+                  label: action.label,
+                  onSelect: () => {
+                    action.onClick();
+                    dismissClient(n.id);
                   },
-                ]
+                }))
               : [];
     return menuGroups(own, [dismissRow(() => removeClient(n.id))]);
   }
@@ -391,7 +396,7 @@ export default function NotificationsPanel() {
                         onRead={() => readMut.mutate(n.id)}
                         onDismiss={() => dismissMut.mutate(n.id)}
                         onOpenScheduler={openScheduler}
-                        onOpenDownloads={openDownloads}
+                        onOpenFile={() => openDone(n)}
                       />
                     );
                   })}
@@ -438,6 +443,11 @@ export default function NotificationsPanel() {
   );
 }
 
+/** A client notice's live actions (they do not survive a reload): its action, then the lesser one. */
+function liveActions(n: ClientNotif): { label: string; onClick: () => void }[] {
+  return [n.action, n.secondaryAction].filter((a) => a !== undefined);
+}
+
 /** A server notification's link, from its type and typed payload (the row's button and its menu). */
 // The download-lifecycle notification types → their `inbox.<key>` copy.
 const DOWNLOAD_LIFECYCLE: Record<string, string | undefined> = {
@@ -500,7 +510,7 @@ function NotificationRow({
   onRead,
   onDismiss,
   onOpenScheduler,
-  onOpenDownloads,
+  onOpenFile,
 }: {
   n: AppNotification;
   t: TFunction;
@@ -510,7 +520,7 @@ function NotificationRow({
   onRead: () => void;
   onDismiss: () => void;
   onOpenScheduler: () => void;
-  onOpenDownloads: () => void;
+  onOpenFile: () => void;
 }) {
   const lang = useTranslation().i18n.language;
   // The maintenance producer ships the affected videos in `data.videos`; list a few titles.
@@ -609,10 +619,10 @@ function NotificationRow({
             variant="link"
             className="text-sm mt-1.5"
             data-nav-open=""
-            onClick={onOpenDownloads}
-            icon={<Download className="w-3.5 h-3.5" />}
+            onClick={onOpenFile}
+            icon={<FolderOpen className="w-3.5 h-3.5" />}
           >
-            {t("inbox.openDownloads")}
+            {t("inbox.openFile")}
           </Button>
         )}
       </div>
@@ -706,19 +716,25 @@ function ClientActivityRow({
             {t("common.accessRequestsReview")}
           </Button>
         ) : (
-          n.action &&
-          !n.dismissed && (
-            <Button
-              variant="link"
-              className="mt-1 text-sm"
-              data-nav-open=""
-              onClick={() => {
-                n.action!.onClick();
-                dismissClient(n.id);
-              }}
-            >
-              {n.action.label}
-            </Button>
+          !n.dismissed &&
+          liveActions(n).length > 0 && (
+            <div className="mt-1 flex flex-wrap gap-x-4">
+              {liveActions(n).map((action, i) => (
+                <Button
+                  key={action.label}
+                  variant="link"
+                  className="text-sm"
+                  // The first is the row's own: Enter on the row runs it.
+                  data-nav-open={i === 0 ? "" : undefined}
+                  onClick={() => {
+                    action.onClick();
+                    dismissClient(n.id);
+                  }}
+                >
+                  {action.label}
+                </Button>
+              ))}
+            </div>
           )
         )}
       </div>