fix(bot): un-reacting from a poll never un-counted the vote

wyr/acronym/nhie/hottake tracked votes only on reaction-add, using
"add to bucket A, remove from bucket B" logic that self-corrects when
switching reactions but not when a reaction is simply removed — nio
never subscribed to RedactionEvent at all, so an un-react was
invisible to the bot. Fixes LotusGuild/matrix#6 (repro: react agree
and disagree, remove disagree, still counted as disagree).

Adds unrecord_* counterparts to each record_* vote function, a
reaction_id -> (poll_event_id, sender) index in Callbacks (only
populated for reactions on messages we're actually tracking, so it
stays bounded) so a later redaction can be traced back to what to
un-count, and wires up RedactionEvent -> callbacks.redaction in bot.py.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

matrixbot/commands.py

@@ -1842,6 +1842,15 @@ def record_wyr_vote(event_id: str, sender: str, key: str) -> None:
         poll["votes"][key].add(sender)
 
 
+def unrecord_wyr_vote(event_id: str, sender: str) -> None:
+    """Called from callbacks when a reaction is removed from a WYR poll message."""
+    poll = _WYR_POLLS.get(event_id)
+    if not poll:
+        return
+    for bucket in poll["votes"].values():
+        bucket.discard(sender)
+
+
 async def _generate_wyr() -> dict | None:
     # Few-shot examples anchor the format so the model doesn't drift
     examples = [
@@ -2680,6 +2689,17 @@ def record_acronym_vote(event_id: str, sender: str, key: str) -> None:
         game.setdefault("votes", {})[sender] = idx  # one vote per person
 
 
+def unrecord_acronym_vote(event_id: str, sender: str) -> None:
+    """Record a numbered-emoji vote removal on an acronym poll."""
+    room_id = _ACRONYM_POLL_IDS.get(event_id)
+    if room_id is None:
+        return
+    game = _ACRONYM_GAMES.get(room_id)
+    if not game or game.get("phase") != "voting":
+        return
+    game.get("votes", {}).pop(sender, None)
+
+
 @command("acronym", "AI picks an acronym — submit the funniest expansion with !ac, then vote!")
 async def cmd_acronym(client: AsyncClient, room_id: str, sender: str, args: str):
     if room_id in _ACRONYM_GAMES:
@@ -3036,6 +3056,14 @@ def record_nhie_reaction(event_id: str, sender: str, key: str) -> None:
         poll["have"].discard(sender)
 
 
+def unrecord_nhie_reaction(event_id: str, sender: str) -> None:
+    poll = _NHIE_POLLS.get(event_id)
+    if not poll:
+        return
+    poll["have"].discard(sender)
+    poll["never"].discard(sender)
+
+
 _NHIE_TOPICS = [
     "travel", "food", "social situations", "school or work", "technology",
     "outdoor adventures", "relationships", "embarrassing moments",
@@ -3138,6 +3166,14 @@ def record_hottake_reaction(event_id: str, sender: str, key: str) -> None:
         poll["agree"].discard(sender)
 
 
+def unrecord_hottake_reaction(event_id: str, sender: str) -> None:
+    poll = _HOTTAKE_POLLS.get(event_id)
+    if not poll:
+        return
+    poll["agree"].discard(sender)
+    poll["disagree"].discard(sender)
+
+
 _HOTTAKE_TOPICS = [
     "food and cooking", "music genres", "social media and technology",
     "sports and fitness", "video games", "movies and TV shows",