feat(a11y): label form controls + overlays (P3-4)

Accessible names for ~15 controls that lacked them: invite/join/create-room/
account-data/image-pack/private-note/power-level inputs (visible <label htmlFor>
where a label exists, else aria-label); the two range sliders (night-light
intensity, noise-gate threshold); the soundboard file input; media <video>
elements; and the Media Gallery (region) + Search (dialog) overlays. Hidden
notification/preview <audio> marked aria-hidden.

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

src/app/features/common-settings/permissions/PowersEditor.tsx

@@ -147,6 +147,7 @@ function EditPower({ maxPower, power, tag, onSave, onClose }: EditPowerProps) {
             <Text size="L400">Name</Text>
             <Input
               name="nameInput"
+              aria-label="Power level name"
               defaultValue={tag?.name}
               placeholder="Bot"
               size="300"
@@ -160,6 +161,7 @@ function EditPower({ maxPower, power, tag, onSave, onClose }: EditPowerProps) {
             <Input
               defaultValue={power}
               name="powerInput"
+              aria-label="Power level value"
               size="300"
               variant={typeof power === 'number' ? 'SurfaceVariant' : 'Secondary'}
               radii="300"

src/app/features/room/MediaGallery.tsx

@@ -186,8 +186,8 @@ function LightboxMedia({
       )}
       {media.status === 'ok' &&
         (item.msgtype === MsgType.Video ? (
-          // eslint-disable-next-line jsx-a11y/media-has-caption
           <video
+            aria-label="Video attachment"
             src={media.url}
             controls
             autoPlay
@@ -261,7 +261,7 @@ function Lightbox({
           escapeDeactivates: false,
         }}
       >
-        {/* eslint-disable-next-line jsx-a11y/no-static-element-interactions */}
+        {}
         <div
           role="dialog"
           aria-modal
@@ -640,13 +640,15 @@ export function MediaGallery({ room, onClose }: MediaGalleryProps) {
         className={classNames(css.MediaGalleryDrawer, ContainerColor({ variant: 'Background' }))}
         shrink="No"
         direction="Column"
+        role="region"
+        aria-labelledby="media-gallery-title"
       >
         {/* Header */}
         <Header variant="Background" size="600" className={css.MediaGalleryHeader}>
           <Box grow="Yes" alignItems="Center" gap="200">
             <Icon size="200" src={Icons.Photo} />
             <Box grow="Yes">
-              <Text size="H4" truncate>
+              <Text id="media-gallery-title" size="H4" truncate>
                 Media Gallery
               </Text>
             </Box>

src/app/features/room/PollCreator.tsx

@@ -142,7 +142,6 @@ export function PollCreator({ roomId, onClose }: PollCreatorProps) {
                   placeholder="Ask a question…"
                   value={question}
                   onChange={(e: React.ChangeEvent<HTMLInputElement>) => setQuestion(e.target.value)}
-                  // eslint-disable-next-line jsx-a11y/no-autofocus
                   autoFocus
                 />
               </Box>
@@ -151,7 +150,6 @@ export function PollCreator({ roomId, onClose }: PollCreatorProps) {
               <Box direction="Column" gap="200">
                 <Text size="L400">Options</Text>
                 {options.map((opt, index) => (
-                  // eslint-disable-next-line react/no-array-index-key
                   <Box key={index} alignItems="Center" gap="200">
                     <Input
                       style={{ flex: 1 }}

src/app/features/search/Search.tsx

@@ -247,7 +247,6 @@ export function Search({ requestClose }: SearchProps) {
         <FocusTrap
           focusTrapOptions={{
             initialFocus: () => inputRef.current,
-            returnFocusOnDeactivate: false,
             allowOutsideClick: true,
             clickOutsideDeactivates: true,
             onDeactivate: requestClose,
@@ -257,7 +256,13 @@ export function Search({ requestClose }: SearchProps) {
             },
           }}
         >
-          <Modal size="400" style={{ maxHeight: toRem(400), borderRadius: config.radii.R500 }}>
+          <Modal
+            size="400"
+            role="dialog"
+            aria-modal="true"
+            aria-label="Search"
+            style={{ maxHeight: toRem(400), borderRadius: config.radii.R500 }}
+          >
             <Box
               shrink="No"
               style={{ padding: config.space.S400, paddingBottom: 0 }}
@@ -270,6 +275,7 @@ export function Search({ requestClose }: SearchProps) {
                 radii="400"
                 outlined
                 placeholder="Search"
+                aria-label="Search rooms"
                 before={<Icon size="200" src={Icons.Search} />}
                 onChange={handleInputChange}
                 onKeyDown={handleInputKeyDown}

src/app/features/settings/general/General.tsx

@@ -531,6 +531,7 @@ function Appearance() {
               Intensity: {nightLightOpacity}%
             </Text>
             <input
+              aria-label="Night light intensity"
               type="range"
               min={5}
               max={80}
@@ -1663,6 +1664,7 @@ function Calls() {
                     <Text size="T200">{callDenoiseGateThreshold} dB</Text>
                   </Box>
                   <input
+                    aria-label="Noise gate threshold"
                     type="range"
                     min="-100"
                     max="0"