feat(polls): complete the poll lifecycle — voting, undisclosed, end, spec-correct

Upgrade the MSC3381 poll feature from a leaky half-implementation to a complete,
cross-client-correct one:

- End/close a poll (creator or redact-PL mod) via inline confirm → m.poll.end;
  locks voting, reveals results, marks winner(s); only pre-end responses count.
- Honor poll kind: undisclosed polls hide counts/percent/bars/total until ended
  (creator gets a Show-live-results vs Hidden-until-ended toggle; default live).
  Previously every poll was created undisclosed yet the UI leaked live results.
- Enforce max_selections for multi-choice; radiogroup/checkbox a11y with arrow-key
  roving and an AT-announced winner.
- Robust, dual-namespace wire handling: parse BOTH stable (m.poll/m.id/m.selections)
  and unstable (org.matrix.msc3381.poll.*) by hand — matrix-js-sdk 41.7.0's
  PollStart/Response parsers only understand the unstable bodies, so delegating to
  them broke every stable poll (caught in agent review). Use the SDK Poll model only
  for end validation + before-end filtering.
- Pure tally/visibility/winner/parse logic extracted to utils/poll.ts with 14 tests
  incl. a stable/unstable wire-format round-trip.

Reviewed by 3 agents (spec/cross-client, logic, a11y/UI); findings applied.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/features/room/PollCreator.tsx

@@ -34,6 +34,9 @@ export function PollCreator({ roomId, onClose }: PollCreatorProps) {
   const [question, setQuestion] = useState('');
   const [options, setOptions] = useState<string[]>(['', '']);
   const [isMultiple, setIsMultiple] = useState(false);
+  // Results visibility: disclosed (live results, default) vs undisclosed (hidden
+  // until the poll is ended).
+  const [disclosed, setDisclosed] = useState(true);
   const [submitting, setSubmitting] = useState(false);
   const [error, setError] = useState<string | null>(null);
 
@@ -73,14 +76,20 @@ export function PollCreator({ roomId, onClose }: PollCreatorProps) {
     setError(null);
     setSubmitting(true);
     try {
+      // Text fallback for clients that don't understand polls: the question + a
+      // numbered list of the options.
+      const fallbackBody = [
+        trimmedQuestion,
+        ...filledOptions.map((o, i) => `${i + 1}. ${o}`),
+      ].join('\n');
       await mx.sendEvent(roomId, 'm.poll.start' as any, {
         'm.poll': {
           question: { 'm.text': trimmedQuestion },
           answers: filledOptions.map((o, i) => ({ 'm.id': `${i}`, 'm.text': o })),
           max_selections: isMultiple ? filledOptions.length : 1,
-          kind: 'm.poll.undisclosed',
+          kind: disclosed ? 'm.poll.disclosed' : 'm.poll.undisclosed',
         },
-        body: trimmedQuestion,
+        body: fallbackBody,
         msgtype: 'm.text',
       });
       onClose();
@@ -216,6 +225,31 @@ export function PollCreator({ roomId, onClose }: PollCreatorProps) {
                 </Box>
               </Box>
 
+              {/* Results visibility */}
+              <Box direction="Column" gap="100">
+                <Text size="L400">Results</Text>
+                <Box gap="200">
+                  {(['live', 'hidden'] as const).map((mode) => {
+                    const active = mode === 'live' ? disclosed : !disclosed;
+                    return (
+                      <Button
+                        key={mode}
+                        type="button"
+                        size="300"
+                        variant="Primary"
+                        fill={active ? 'Solid' : 'None'}
+                        radii="300"
+                        onClick={() => setDisclosed(mode === 'live')}
+                      >
+                        <Text size="B300">
+                          {mode === 'live' ? 'Show live results' : 'Hidden until ended'}
+                        </Text>
+                      </Button>
+                    );
+                  })}
+                </Box>
+              </Box>
+
               {/* Error */}
               {error && (
                 <Text size="T300" style={{ color: color.Critical.Main }}>

src/app/features/room/RoomTimeline.tsx

@@ -1314,13 +1314,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
                   mEvent.getType() === 'm.poll.start' ||
                   mEvent.getType() === 'org.matrix.msc3381.poll.start'
                 )
-                  return (
-                    <PollContent
-                      content={mEvent.getContent()}
-                      roomId={room.roomId}
-                      eventId={mEvent.getId() ?? undefined}
-                    />
-                  );
+                  return <PollContent mEvent={mEvent} room={room} canRedact={canRedact} />;
                 if (mEvent.getType() === MessageEvent.RoomMessageEncrypted)
                   return (
                     <Text>
@@ -1449,11 +1443,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
             {mEvent.isRedacted() ? (
               <RedactedContent reason={mEvent.getUnsigned().redacted_because?.content.reason} />
             ) : (
-              <PollContent
-                content={mEvent.getContent()}
-                roomId={room.roomId}
-                eventId={mEvent.getId() ?? undefined}
-              />
+              <PollContent mEvent={mEvent} room={room} canRedact={canRedact} />
             )}
           </Message>
         );
@@ -1506,11 +1496,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
             {mEvent.isRedacted() ? (
               <RedactedContent reason={mEvent.getUnsigned().redacted_because?.content.reason} />
             ) : (
-              <PollContent
-                content={mEvent.getContent()}
-                roomId={room.roomId}
-                eventId={mEvent.getId() ?? undefined}
-              />
+              <PollContent mEvent={mEvent} room={room} canRedact={canRedact} />
             )}
           </Message>
         );