refactor(DP15): centralize sendStateEvent as-any cast in typed helper

Add a typed `sendStateEvent(mx, roomId, eventType, content, stateKey?)`
helper in utils/room.ts that mirrors the DP16 account-data helper pattern.
The SDK's typed `sendStateEvent` overload rejects the fork's custom
`StateEvent` enum values, so every call site cast arg 2 to `any` (which
also collapsed the content type). The single `as any` cast now lives inside
the helper; a generic `content: T extends object` keeps each call site's
content type checked.

Route all 32 `mx.sendStateEvent(..., StateEvent.X as any, ...)` casts across
20 files through the helper. The 2 dynamic-string casts in developer-tools
(SendRoomEvent, StateEventEditor) pass a runtime string, not an enum value,
so they stay as-is.

No behavior change.

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

src/app/features/common-settings/general/RoomProfile.tsx

@@ -39,6 +39,7 @@ import { mxcUrlToHttp } from '../../../utils/matrix';
 import { useMatrixClient } from '../../../hooks/useMatrixClient';
 import { useMediaAuthentication } from '../../../hooks/useMediaAuthentication';
 import { StateEvent } from '../../../../types/matrix/room';
+import { sendStateEvent } from '../../../utils/room';
 import { CompactUploadCardRenderer } from '../../../components/upload-card';
 import { useObjectURL } from '../../../hooks/useObjectURL';
 import { createUploadAtom, UploadSuccess } from '../../../state/upload';
@@ -152,16 +153,16 @@ export function RoomProfileEdit({
     useCallback(
       async (roomAvatarMxc?: string | null, roomName?: string, roomTopic?: string) => {
         if (roomAvatarMxc !== undefined) {
-          await mx.sendStateEvent(room.roomId, StateEvent.RoomAvatar as any, {
+          await sendStateEvent(mx, room.roomId, StateEvent.RoomAvatar, {
             url: roomAvatarMxc,
           });
         }
         if (roomName !== undefined) {
-          await mx.sendStateEvent(room.roomId, StateEvent.RoomName as any, { name: roomName });
+          await sendStateEvent(mx, room.roomId, StateEvent.RoomName, { name: roomName });
         }
         if (roomTopic !== undefined) {
           const topicContent = buildTopicContent(roomTopic);
-          await mx.sendStateEvent(room.roomId, StateEvent.RoomTopic as any, topicContent);
+          await sendStateEvent(mx, room.roomId, StateEvent.RoomTopic, topicContent);
         }
       },
       [mx, room.roomId],