[Feature Request]: Show search-filtered playlist videos first as a group

### Guidelines

- [X] I have searched the issue tracker for [open](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aopen+is%3Aissue) and [closed](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aissue+is%3Aclosed) issues that are similar to the feature request I want to file, without success.
- [X] I have searched the [documentation](https://docs.freetubeapp.io/) for information that matches the description of the feature request I want to file, without success.
- [X] This issue contains only one feature request.

### Problem Description

When searching a particular set of videos in a user playlist, I often want to watch the full list of videos in the filtered search results as a group. The only ways to do this currently are to open each video in a separate FT tab (which can be onerous & manual), or using the Back button and pasting the search input again (same issues).

### Proposed Solution

When you search for a set of videos, have those results be cached in a grouping at the top of the `watch-video-playlist` items.

Optional but recommended add-on: A transient `watch-video-playlist` button appears that removes the grouping & places the constituent videos in their proper place in the sort order.

Optional: some type of visual & semantic indicator for the grouping. Like a magnifying glass icon under each video's playlist index and a modified aria label of `Playlist search result`. Or something to that effect.

As far as I know, this is a novel feature that doesn't exist on any platform I know of, so I'd like if we could set a good example and try to make a well-rounded solution if we do decide to implement this.

### Alternatives Considered

Sorting by author & having it reflected in the results (after #5013 is merged) would cover the subset of use cases where I'm looking for a common author, but it's not very comprehensive.

### Issue Labels

ease of use improvement, new feature

### Additional Information

_No response_