fix: ESLint errors, stale disable comments, bundle splitting

- RoomTimeline.tsx: add eslint-disable comment for intentional eventsLength
  dep on timelineSegments useMemo (needed to detect in-place timeline mutations)
- Remove ~47 stale eslint-disable-next-line comments across 28 files for rules
  that are now off in the flat config (no-param-reassign, jsx-a11y/media-has-caption,
  react/no-array-index-key, etc); run prettier to reformat
- vite.config.js: move manualChunks from rollupOptions.output to
  rolldownOptions.output so Rolldown (Vite 8) actually applies it; main bundle
  drops from 3.5 MB to 814 kB gzip-248 kB, matrix-sdk gets its own 1.16 MB
  cacheable chunk

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

src/app/components/CallEmbedProvider.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable jsx-a11y/media-has-caption */
 import React, { ReactNode, useCallback, useEffect, useRef, useState } from 'react';
 import { useAtomValue, useSetAtom } from 'jotai';
 import FocusTrap from 'focus-trap-react';

src/app/components/DeviceVerification.tsx

@@ -137,7 +137,6 @@ function CompareEmoji({ sasData }: { sasData: ShowSasCallbacks }) {
       >
         {sasData.sas.emoji?.map(([emoji, name], index) => (
           <Box
-            // eslint-disable-next-line react/no-array-index-key
             key={`${emoji}${name}${index}`}
             direction="Column"
             gap="100"

src/app/components/LobbySkeleton.tsx

@@ -89,7 +89,6 @@ export function LobbySkeleton() {
           {/* Room list rows */}
           <div style={{ flex: 1, padding: '8px 0' }}>
             {ROOM_ROWS.map((row, i) => (
-              // eslint-disable-next-line react/no-array-index-key
               <div
                 key={i}
                 style={{

src/app/components/Pdf-viewer/PdfViewer.tsx

@@ -1,5 +1,3 @@
-/* eslint-disable no-param-reassign */
-/* eslint-disable jsx-a11y/no-noninteractive-element-interactions */
 import React, { FormEventHandler, MouseEventHandler, useEffect, useRef, useState } from 'react';
 import classNames from 'classnames';
 import {

src/app/components/RoomSkeleton.tsx

@@ -80,7 +80,6 @@ export function RoomSkeleton() {
         {/* Timeline */}
         <div style={{ flex: 1, overflowY: 'hidden', padding: '16px 0' }}>
           {MESSAGES.map((msg, i) => (
-            // eslint-disable-next-line react/no-array-index-key
             <div
               key={i}
               style={{
@@ -103,7 +102,6 @@ export function RoomSkeleton() {
                   <div style={{ ...shimmer, width: '90px', height: '12px', marginBottom: '2px' }} />
                 )}
                 {msg.lines.map((line, j) => (
-                  // eslint-disable-next-line react/no-array-index-key
                   <div key={j} style={{ ...shimmer, width: line.w, height: '14px' }} />
                 ))}
               </div>

src/app/components/editor/Editor.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import React, {
   ClipboardEventHandler,
   KeyboardEventHandler,

src/app/components/editor/input.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import { Descendant, Text } from 'slate';
 import parse from 'html-dom-parser';
 import { ChildNode, Element, isText, isTag } from 'domhandler';

src/app/components/editor/utils.ts

@@ -148,7 +148,6 @@ export const resetEditor = (editor: Editor) => {
 };
 
 export const resetEditorHistory = (editor: Editor) => {
-  // eslint-disable-next-line no-param-reassign
   editor.history = {
     undos: [],
     redos: [],
@@ -228,7 +227,6 @@ export const getPointUntilChar = (
     reverse: options.reverse,
   });
 
-  // eslint-disable-next-line no-restricted-syntax
   for (const point of pointItr) {
     if (!Point.equals(point, cursorPoint) && prevPoint) {
       char = Editor.string(editor, { anchor: point, focus: prevPoint });

src/app/components/image-viewer/ImageViewer.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable jsx-a11y/no-noninteractive-element-interactions */
 import React from 'react';
 import FileSaver from 'file-saver';
 import classNames from 'classnames';

src/app/components/media/Video.tsx

@@ -4,7 +4,6 @@ import * as css from './media.css';
 
 export const Video = forwardRef<HTMLVideoElement, VideoHTMLAttributes<HTMLVideoElement>>(
   ({ className, ...props }, ref) => (
-    // eslint-disable-next-line jsx-a11y/media-has-caption
     <video className={classNames(css.Video, className)} {...props} ref={ref} />
   ),
 );

src/app/components/message/content/AudioContent.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable jsx-a11y/media-has-caption */
 import React, { ReactNode, useCallback, useEffect, useRef, useState } from 'react';
 import { Badge, Chip, Icon, IconButton, Icons, ProgressBar, Spinner, Text, toRem } from 'folds';
 import { EncryptedAttachmentInfo } from 'browser-encrypt-attachment';

src/app/components/text-viewer/TextViewer.tsx

@@ -1,4 +1,3 @@
-/* eslint-disable jsx-a11y/no-noninteractive-element-interactions */
 import React, { ComponentProps, HTMLAttributes, Suspense, forwardRef, lazy } from 'react';
 import classNames from 'classnames';
 import { Box, Chip, Header, Icon, IconButton, Icons, Scroll, Text, as } from 'folds';

src/app/components/upload-card/UploadCardRenderer.tsx

@@ -42,7 +42,6 @@ function PreviewVideo({ fileItem }: PreviewVideoProps) {
   const fileUrl = useObjectURL(originalFile);
 
   return (
-    // eslint-disable-next-line jsx-a11y/media-has-caption
     <video
       style={{
         objectFit: 'contain',