fix(ui): honest tab titles and a download field that names every site

Signed out, the tab read Home's question over the sign-in form; the legal
pages read just "Siftlode". The download field asked only for a YouTube
link although Facebook and the rest download too.

frontend/src/components/NavigationProvider.tsx

@@ -1,5 +1,6 @@
 import { useCallback, useEffect, useMemo, useRef, useState, type ReactNode } from "react";
 import { useTranslation } from "react-i18next";
+import { useMe } from "../lib/useMe";
 import { urlWithParams, type Page } from "../lib/urlState";
 import { LOGS_KEYS } from "../lib/logsUrlState";
 import { pageTitleKey } from "../lib/pageMeta";
@@ -154,16 +155,20 @@ export function NavigationProvider({ children }: { children: ReactNode }) {
   }, [page]);
 
   // Reflect the current module in the browser tab title. Feed = brand only; an open channel page
-  // shows the channel name.
+  // shows the channel name. Signed out, the page on screen is the public landing whatever `page`
+  // says — the tab read "What should I watch?" over the sign-in form (prod UAT 2026-09-19).
+  const signedIn = useMe() != null;
   useEffect(() => {
     const brand = "Siftlode";
-    const label = channelView
-      ? channelView.name || t("header.channelManager")
-      : page === "feed"
-        ? null
-        : t(pageTitleKey(page));
+    const label = !signedIn
+      ? null
+      : channelView
+        ? channelView.name || t("header.channelManager")
+        : page === "feed"
+          ? null
+          : t(pageTitleKey(page));
     document.title = label ? `${label} · ${brand}` : brand;
-  }, [page, channelView, i18n.language, t]);
+  }, [signedIn, page, channelView, i18n.language, t]);
 
   // In-app Back/Forward: stamp the initial entry with the current page (mirrored to the address bar),
   // then sync state from history.state on popstate — the browser restores each entry's URL for us, so