feat: quick emoji reactions on hover, in-app notification toasts, mention pulse audit

P5-17: MessageQuickReactions moved from 3-dots menu to hover toolbar;
shows 5 recent emoji directly on hover. Clicking a quick-reaction also
closes any open emoji picker (setEmojiBoardAnchor). Line separator
removed from component.

P5-7: LotusToastContainer slides in from bottom-right when window is
focused — replaces OS notification for in-focus events. Correct room
path (DM vs home) derived from mDirectAtom. Invite toast routes to
inbox. 4s auto-dismiss. Full TDS styling via CSS custom properties.

P5-8: Confirmed already implemented upstream (MentionHighlightPulse,
0.6s scale+glow, one-shot, prefers-reduced-motion). Marked complete.

Code-review fixes: toast navigation used nonexistent /room/ route;
emoji picker stayed open after toolbar quick-reaction.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/features/room/message/Message.tsx

@@ -152,7 +152,7 @@ type MessageQuickReactionsProps = {
 export const MessageQuickReactions = as<'div', MessageQuickReactionsProps>(
   ({ onReaction, ...props }, ref) => {
     const mx = useMatrixClient();
-    const recentEmojis = useRecentEmoji(mx, 4);
+    const recentEmojis = useRecentEmoji(mx, 5);
 
     if (recentEmojis.length === 0) return <span />;
     return (
@@ -180,7 +180,6 @@ export const MessageQuickReactions = as<'div', MessageQuickReactionsProps>(
             </IconButton>
           ))}
         </Box>
-        <Line size="300" />
       </>
     );
   },
@@ -1035,6 +1034,14 @@ export const Message = React.memo(
                       </IconButton>
                     </PopOut>
                   )}
+                  {canSendReaction && (
+                    <MessageQuickReactions
+                      onReaction={(key, shortcode) => {
+                        onReactionToggle(mEvent.getId()!, key, shortcode);
+                        setEmojiBoardAnchor(undefined);
+                      }}
+                    />
+                  )}
                   <IconButton
                     onClick={onReplyClick}
                     data-event-id={mEvent.getId()}
@@ -1085,14 +1092,6 @@ export const Message = React.memo(
                         }}
                       >
                         <Menu>
-                          {canSendReaction && (
-                            <MessageQuickReactions
-                              onReaction={(key, shortcode) => {
-                                onReactionToggle(mEvent.getId()!, key, shortcode);
-                                closeMenu();
-                              }}
-                            />
-                          )}
                           <Box direction="Column" gap="100" className={css.MessageMenuGroup}>
                             {canSendReaction && (
                               <MenuItem