feat(polls): implement MSC3381 polls

[Just-Insane]

Description

> ⚠️ Merge together with SableClient/docs#12

Implements Matrix polls (MSC3381) with a creator dialog and timeline renderer.

• New PollCreatorDialog — question, 2–20 answers, disclosed/undisclosed type, voter visibility toggle (show/hide voter names), poll duration (presets: 1h / 12h / 24h / 48h / 1 week / custom date-time)
• New PollEvent timeline renderer — vote buttons, live/final results bars, expandable voter lists per answer, expiry countdown in footer, auto-expire enforcement, end-poll action
• Poll state assembled inline in PollEvent from org.matrix.msc3381.poll.start, .poll.response, and .poll.end events via paginated room timeline; respects show_voter_names and closes_at fields. Also handles stable m.poll.* types.
• /poll slash command in RoomInput, gated by features.polls in config.json (defaults false)
• Supports both stable (m.poll.*) and unstable (org.matrix.msc3381.poll.*) event types
• Handles encrypted poll responses via MatrixEventEvent.Decrypted listener
• Multi-select polls render with checkboxes; single-select with radio buttons
• Keyboard accessibility via FocusOutline focus-visible styles on poll options

Spec: MSC3381
Related upstream issue: cinnyapp/cinny#563
Documentation: SableClient/docs#12

Fixes #

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

AI disclosure:

• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).

Poll state is assembled inline in PollEvent by paginating the room timeline to collect poll.response events keyed by sender, deduplicating so only the last vote per user counts, and tallying totals and percentages. PollEvent renders the resulting state as vote buttons with fill-bars; it re-fetches on RoomEvent.Timeline and MatrixEventEvent.Decrypted so it stays live even for encrypted responses. PollCreatorDialog builds the m.poll.start content with crypto.randomUUID() answer IDs and sends via mx.sendEvent. The /poll slash command is conditionally available based on clientConfig.features?.polls. The show_voter_names flag is a client-side display hint stored in the poll start event; the closes_at field is a Unix ms timestamp enforced client-side (voting blocked after expiry, UI shows countdown).

[dozro]

is it using the ui you showed in matrix chat or the ui of cinnyapp/cinny#2763 ?

[Just-Insane]

is it using the ui you showed in matrix chat or the ui of cinnyapp/cinny#2763 ?

The UI from Cinny

[Copilot]

Pull request overview

Implements Matrix MSC3381 poll support in the room timeline, including poll creation UI, vote/end handling, and a feature-flag gate via client config.

Changes:

• Add poll event types/SDK exports and a features.polls client-config flag (default false).
• Add PollCreatorDialog (poll creation) and PollEvent (timeline renderer + tallying/end action), plus supporting styles and tests.
• Integrate poll rendering/filtering into timeline processing and add a /poll command pathway in RoomInput.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/types/matrix/room.ts	Adds MSC3381 (unstable) poll event types to the room message type enum.
src/types/matrix-sdk.ts	Re-exports poll constants/types from matrix-js-sdk for app usage.
src/app/hooks/useCommands.ts	Adds /poll command entry for command discovery/autocomplete.
src/app/hooks/useClientConfig.ts	Extends client config typing with features.polls.
src/app/hooks/timeline/useTimelineEventRenderer.tsx	Adds timeline rendering for poll start events and suppresses rendering for response/end events.
src/app/hooks/timeline/useProcessedTimeline.ts	Filters poll response/end events so they don’t appear as timeline items.
src/app/features/room/RoomInput.tsx	Adds feature-gated poll creator dialog launch (via /poll) and sends poll start events.
src/app/features/room/poll/PollEvent.tsx	Implements poll content extraction, tally computation, voting, ending, and results UI.
src/app/features/room/poll/pollEvent.test.ts	Adds unit tests for poll parsing, tallying, and expiry formatting.
src/app/features/room/poll/PollEvent.css.ts	Adds styles for poll option controls and layout.
src/app/features/room/poll/PollCreatorDialog.tsx	Implements poll creation dialog (question/options/visibility/expiry/max selections).
src/app/features/room/poll/PollCreatorDialog.css.ts	Adds styles for the poll creation dialog.
src/app/features/room/poll/index.ts	Exports poll feature components/types.
config.json	Adds features.polls: false feature flag to config.
.changeset/feat-polls.md	Adds changeset entry for the new polls feature.

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[dozro]

the amount of commits and line changes this pr wants to merge seems a bit off for the problem stated 🤔

[Just-Insane]

Thanks for the note! The branch was initially developed on top of my integration branch (which merges all feature branches together for local testing), which bloated the commit/diff count significantly beyond what the feature itself required. The branch has since been rebased onto dev directly with only its own commits, so the diff should now reflect just the polls implementation. Apologies for the noise!