AND-1180

Goal

The poll-results bottom sheet, the per-option votes screen, the comments dialog, and the more-options dialog were hard to navigate with TalkBack: the screen title wasn't announced on open, sub-section labels weren't navigable as headings, vote/comment rows produced one focus per child element (avatar, name, date), and the radio/checkbox in the more-options dialog was unlabeled. This PR fixes all of that so each row is a single focus with a meaningful announcement, and dialog titles identify their screen.

Implementation

• PollDialogHeader (shared by all four poll dialogs): title Text carries heading() semantics, and the header sends a programmatic view.announceForAccessibility(title) on first composition. ModalBottomSheet swallows the standard paneTitle window-state-changed event, so programmatic announce is the reliable workaround.
• PollVoteItem (shared by results + per-option votes screens): the row merges its descendants so each vote announces as one focus (avatar + name + date).
• PollViewResultDialog: option header (Option N) + summary row (option text + winner badge + vote count) wrapped in a merged Column with heading() — one focus per option summary, navigable via TalkBack's heading shortcut. Question section also merged with heading().
• PollOptionVotesDialog: the trophy-and-vote-count header row above the votes list is merged.
• PollAnswers: each comment card merges the answer text with the user/timestamp row into one focus; the "Update Your Comment" button stays as its own separate focus.
• PollMoreOptionsDialog: applies the same pattern as the just-merged inline poll (PollMessageContent, Improve poll vote row TalkBack accessibility #6461): each option row is toggleable with Role.RadioButton (single-vote polls) or Role.Checkbox (multi-vote), the RadioCheck is hidden from accessibility since the toggleable row already conveys state, the vote count gets a plural contentDescription, and the LinearProgressIndicator is removed from the semantics tree (the row already carries the count). Question section also merged with heading().

No visible UI changes; layout, colours, and behaviour are unchanged.

Testing

1. Enable TalkBack.
2. Long-press a poll message and open View Results:
   • Sheet open should announce the screen title ("Poll Results").
   • Swiping right should focus the back button, then the question section (one focus, announced as a heading), then each option summary ("Option 1, A, 3 votes" / "Option 1, A, Winner badge, 3 votes"), then each vote row as one focus, then the "Show all" button (when present), then the total votes count.
   • TalkBack's heading-navigation shortcut should jump between the question and each option.
3. From the results screen, tap Show all on an option:
   • The per-option votes screen should announce its title (the option text).
   • The top header row should announce "Winner badge, 3 votes" as one focus (when the option is the winner).
   • Each vote announces as a single merged focus.
4. Open View Comments on a poll with answers:
   • Title should be announced as "Poll Comments".
   • Each comment card should announce as one focus (comment text, user, timestamp). The "Update Your Comment" button (on the current user's own answer) is a separate focus.
5. Open a poll with more options than the inline preview shows, tap Show all options:
   • Title should be announced.
   • Each option row should announce as one focus, including option text, vote count and toggle state ("not checked / checked, RadioButton" or "Checkbox"); double-tap toggles the vote.
   • The question section should announce as one focus and act as a heading.

Summary by CodeRabbit

• Improvements
  • Enhanced accessibility support across poll components with improved screen reader compatibility.
  • Added semantic structure for better navigation and content description of poll titles and options.
  • Improved vote interaction feedback with clearer accessibility descriptions for vote counts.