Polls, quotes and edits from the composer

The composer can hold a poll instead of media (two to four choices, a
length, one choice or several), quote a post (offered on a card when the
server says the persona may quote it), and edit the persona's own post: its
words and warning come from /source, and saving keeps its media,
visibility and poll. A card's menu offers Edit and Quote, and now opens
sideways: upwards, the first card's menu was cut off by the top of the
feed. The e2e tests publish a poll, edit a post and quote it, each checked
on PrivaPub.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

CLAUDE.md

@@ -228,6 +228,9 @@ supplies:
   lists, notifications, public feeds, threads around the opened post, profiles; none for favourites, bookmarks,
   conversations and search), and the card leaves the post out (hide), folds it behind the filter's title (warn) or blurs
   its media (blur).
+- **The composer** (`Components/Composer.razor`) writes a post, a reply (`InReplyTo`), a quote (`Quoting`, offered on a
+  card when the server says the persona may quote it) or an edit of the persona's own post (`Editing`: its words and
+  warning from `/source`, a PUT that keeps its media, visibility and poll); a post can hold a poll instead of media.
 - **Scheduled posts** (`Pages/Scheduled.razor` at `/scheduled`): the composer's clock button gives a Mastodon API post a
   time (`scheduled_at`, at least five minutes ahead; located and group posts have none); the page moves or drops them.
 - **Explore** (`Pages/Explore.razor` at `/explore`): trending hashtags, posts and links (PrivaPub's, from public posts