fix(composer): collapse mobile action buttons behind a "+" overflow menu

On phones the composer's 7-8 secondary action buttons wrapped into a tall
multi-row stack ("massive height"). Mobile now shows a single compact row —
[ + | input | emoji | send ] — where "+" toggles a collapsible row (above the
formatting toolbar) holding attach, GIF, location, poll, voice, formatting and
schedule. Desktop is unchanged (isMobile === false; the mobile branches are
never entered and composerOverflow stays null).

The after-builder stashes the collapsed buttons in a render-local `let` that
the bottom slot reads; safe because JSX props evaluate in source order within
one render (verified by review). Emoji/Send stay inline; the emoji and GIF
PopOut anchors still resolve wherever their button renders.

Review fixes folded in: the "+" toggle uses aria-expanded + aria-controls
(dropped the redundant aria-pressed) pointing at the labelled role="group"
overflow row; the voice recorder's idle mic button gets the @media-gated
MobileTouchTarget 44px target so the overflow row is uniformly tappable.

Two review agents (correctness + UX/a11y); gate-green (tsc, eslint, prettier,
914 tests, build). Visual confirmation still wants a real device per
LOTUS_TESTING.

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

src/app/components/VoiceMessageRecorder.tsx

@@ -2,6 +2,7 @@ import React, { useCallback, useEffect, useRef, useState } from 'react';
 import { Box, Icon, IconButton, Icons, Text, color, config, toRem } from 'folds';
 import { useSetting } from '../state/hooks/settings';
 import { settingsAtom } from '../state/settings';
+import { MobileTouchTarget } from '../styles/mobile.css';
 
 type RecorderState = 'idle' | 'recording' | 'paused' | 'preview';
 
@@ -239,6 +240,7 @@ export function VoiceMessageRecorder({ onSend, onError }: VoiceRecorderProps) {
   if (state === 'idle') {
     return (
       <IconButton
+        className={MobileTouchTarget}
         onClick={startRecording}
         aria-label="Record voice message"
         variant="SurfaceVariant"

src/app/features/room/RoomInput.tsx

@@ -230,7 +230,13 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
 
     const [toolbar, setToolbar] = useSetting(settingsAtom, 'editorToolbar');
     const [composerToolbarButtons] = useSetting(settingsAtom, 'composerToolbarButtons');
-    const touchTarget = mobileOrTablet() ? { minWidth: '44px', minHeight: '44px' } : undefined;
+    const isMobile = mobileOrTablet();
+    // On phones the composer's secondary action buttons (attach, GIF, poll,
+    // location, voice, formatting, schedule) collapse behind a "+" toggle so the
+    // input stays one compact row instead of wrapping into a tall stack. Emoji +
+    // Send remain inline. Desktop keeps everything inline (isMobile === false).
+    const [mobileToolsOpen, setMobileToolsOpen] = useState(false);
+    const touchTarget = isMobile ? { minWidth: '44px', minHeight: '44px' } : undefined;
     const showFormat = composerToolbarButtons?.showFormat ?? true;
     const showEmoji = composerToolbarButtons?.showEmoji ?? true;
     const showSticker = composerToolbarButtons?.showSticker ?? true;
@@ -876,6 +882,12 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
       );
     }
 
+    // Mobile "+" overflow: the `after` builder stashes the collapsed secondary
+    // buttons here and the `bottom` slot renders them when the toggle is open.
+    // React evaluates JSX props in source order (before → after → bottom), so
+    // `after` assigns this before `bottom` reads it within the same render.
+    let composerOverflow: ReactNode = null;
+
     return (
       <div ref={ref}>
         {selectedFiles.length > 0 && (
@@ -1035,16 +1047,31 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             )
           }
           before={
-            <IconButton
-              onClick={() => pickFile('*')}
-              aria-label="Attach file"
-              variant="SurfaceVariant"
-              size="300"
-              radii="300"
-              style={touchTarget}
-            >
-              <Icon src={Icons.PlusCircle} />
-            </IconButton>
+            isMobile ? (
+              <IconButton
+                onClick={() => setMobileToolsOpen((open) => !open)}
+                aria-label="More actions"
+                aria-expanded={mobileToolsOpen}
+                aria-controls="composer-more-actions"
+                variant="SurfaceVariant"
+                size="300"
+                radii="300"
+                style={touchTarget}
+              >
+                <Icon src={mobileToolsOpen ? Icons.Cross : Icons.Plus} />
+              </IconButton>
+            ) : (
+              <IconButton
+                onClick={() => pickFile('*')}
+                aria-label="Attach file"
+                variant="SurfaceVariant"
+                size="300"
+                radii="300"
+                style={touchTarget}
+              >
+                <Icon src={Icons.PlusCircle} />
+              </IconButton>
+            )
           }
           after={(() => {
             const formatButton = showFormat ? (
@@ -1306,9 +1333,37 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
               }
             });
 
+            // Mobile: keep only emoji/sticker inline beside Send; the rest move
+            // into the "+" overflow row (rendered via `bottom`), led by the attach
+            // button that `before` gives up on mobile. Desktop renders all inline.
+            const emojiInline = orderedButtons.filter(
+              (node) => React.isValidElement(node) && node.key === 'showEmojiSticker',
+            );
+            const overflowButtons = orderedButtons.filter(
+              (node) => !(React.isValidElement(node) && node.key === 'showEmojiSticker'),
+            );
+            if (isMobile) {
+              composerOverflow = (
+                <>
+                  <IconButton
+                    key="showAttach"
+                    onClick={() => pickFile('*')}
+                    aria-label="Attach file"
+                    variant="SurfaceVariant"
+                    size="300"
+                    radii="300"
+                    style={touchTarget}
+                  >
+                    <Icon src={Icons.PlusCircle} />
+                  </IconButton>
+                  {overflowButtons}
+                </>
+              );
+            }
+
             return (
               <>
-                {orderedButtons}
+                {isMobile ? emojiInline : orderedButtons}
                 {gifError && (
                   <Text
                     size="T200"
@@ -1365,12 +1420,30 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             );
           })()}
           bottom={
-            toolbar && (
-              <div>
-                <Line variant="SurfaceVariant" size="300" />
-                <Toolbar />
-              </div>
-            )
+            <>
+              {isMobile && mobileToolsOpen && composerOverflow && (
+                <div>
+                  <Line variant="SurfaceVariant" size="300" />
+                  <Box
+                    id="composer-more-actions"
+                    role="group"
+                    aria-label="More actions"
+                    alignItems="Center"
+                    gap="100"
+                    wrap="Wrap"
+                    style={{ padding: config.space.S200 }}
+                  >
+                    {composerOverflow}
+                  </Box>
+                </div>
+              )}
+              {toolbar && (
+                <div>
+                  <Line variant="SurfaceVariant" size="300" />
+                  <Toolbar />
+                </div>
+              )}
+            </>
           }
         />
         {pollOpen && <PollCreator room={room} roomId={roomId} onClose={() => setPollOpen(false)} />}