Fix: Preserve ?v= parameter when auto-redirecting to For You feed

When a user visits a direct video link (e.g. `/?v=...`) while logged in,
the application auto-authenticates and redirects the view to `#view=for-you`.
Previously, `setHashView` unconditionally removed all query parameters, causing
the video modal to fail to open because the `v` parameter was lost before it could be read.

This change:
1.  Updates `setHashView` to accept an options object, allowing specific parameters to be preserved.
2.  Updates `handleAuthLogin` in `app.js` to detect if a `v` parameter is present and request its preservation during the view switch.

js/app.js

@@ -4332,8 +4332,11 @@ class Application {
     const currentView = getHashViewName();
     const normalizedView =
       typeof currentView === "string" ? currentView.toLowerCase() : "";
+    const urlParams = new URLSearchParams(window.location.search);
+    const hasVideoParam = urlParams.has("v");
+
     if (!normalizedView || normalizedView === "most-recent-videos") {
-      setHashView("for-you");
+      setHashView("for-you", { preserveVideoParam: hasVideoParam });
     }
 
     const rawProviderId =