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/hooks/useForceUpdate.js

@@ -1,4 +1,3 @@
-/* eslint-disable import/prefer-default-export */
 import { useState } from 'react';
 
 export function useForceUpdate() {

src/app/hooks/usePowerLevels.ts

@@ -46,12 +46,10 @@ const fillMissingPowers = (powerLevels: IPowerLevels): IPowerLevels =>
     const keys = Object.keys(DEFAULT_POWER_LEVELS) as unknown as (keyof IPowerLevels)[];
     keys.forEach((key) => {
       if (draftPl[key] === undefined) {
-        // eslint-disable-next-line no-param-reassign
         draftPl[key] = DEFAULT_POWER_LEVELS[key] as any;
       }
     });
     if (draftPl.notifications && typeof draftPl.notifications.room !== 'number') {
-      // eslint-disable-next-line no-param-reassign
       draftPl.notifications.room = DEFAULT_POWER_LEVELS.notifications.room;
     }
     return draftPl;
@@ -236,23 +234,22 @@ export const applyPermissionPower = (
     if (typeof location.key === 'string') {
       const users = powerLevels.users ?? {};
       users[location.key] = power;
-      // eslint-disable-next-line no-param-reassign
+
       powerLevels.users = users;
       return powerLevels;
     }
-    // eslint-disable-next-line no-param-reassign
+
     powerLevels.users_default = power;
     return powerLevels;
   }
   if ('action' in location) {
-    // eslint-disable-next-line no-param-reassign
     powerLevels[location.key] = power;
     return powerLevels;
   }
   if ('notification' in location) {
     const notifications = powerLevels.notifications ?? {};
     notifications[location.key] = power;
-    // eslint-disable-next-line no-param-reassign
+
     powerLevels.notifications = notifications;
     return powerLevels;
   }
@@ -260,11 +257,11 @@ export const applyPermissionPower = (
     if (typeof location.key === 'string') {
       const events = powerLevels.events ?? {};
       events[location.key] = power;
-      // eslint-disable-next-line no-param-reassign
+
       powerLevels.events = events;
       return powerLevels;
     }
-    // eslint-disable-next-line no-param-reassign
+
     powerLevels.state_default = power;
     return powerLevels;
   }
@@ -272,11 +269,11 @@ export const applyPermissionPower = (
   if (typeof location.key === 'string') {
     const events = powerLevels.events ?? {};
     events[location.key] = power;
-    // eslint-disable-next-line no-param-reassign
+
     powerLevels.events = events;
     return powerLevels;
   }
-  // eslint-disable-next-line no-param-reassign
+
   powerLevels.events_default = power;
   return powerLevels;
 };

src/app/hooks/useRoomLatestRenderedEvent.ts

@@ -1,4 +1,3 @@
-/* eslint-disable no-continue */
 import { MatrixEvent, Room, RoomEvent, RoomEventHandlerMap } from 'matrix-js-sdk';
 import { useEffect, useState } from 'react';
 import { settingsAtom } from '../state/settings';