Support Additional Media Through a Media Library Button

Enhancement request: In "Classic P2" the Add Media button triggers the Insert Media modal similar to if one were posting from wp-admin. In O2 this is replaced by an Add Image button that jumps straight to upload, rather than offering the additional elements that Insert Media offers: Galleries, Playlists, and the future possibilities of shortcodes via Shortcake (https://github.com/wp-shortcake/shortcake). Could O2 support front end media options similar to P2?

Start by comparing Classic P2's Add Media and Insert Media behavior with O2's Add Image flow, including the wp-admin media options. Review how Galleries, Playlists, and the proposed Shortcake integration relate to the front-end composer; done means O2 offers the requested media-library options rather than only direct image upload.

Written by the indexing model from the issue text.