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/room-settings/RoomServerACL.tsx

@@ -24,6 +24,7 @@ import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { useRoom } from '../../hooks/useRoom';
 import { useStateEvent } from '../../hooks/useStateEvent';
 import { StateEvent } from '../../../types/matrix/room';
+import { sendStateEvent } from '../../utils/room';
 import { usePowerLevels, readPowerLevel } from '../../hooks/usePowerLevels';
 import { useRoomCreators } from '../../hooks/useRoomCreators';
 import { useRoomPermissions } from '../../hooks/useRoomPermissions';
@@ -250,7 +251,7 @@ export function RoomServerACL({ requestClose }: RoomServerACLProps) {
   // Save handler
   const [saveState, save] = useAsyncCallback(
     useCallback(async () => {
-      await mx.sendStateEvent(room.roomId, StateEvent.RoomServerAcl as any, {
+      await sendStateEvent(mx, room.roomId, StateEvent.RoomServerAcl, {
         allow: allowList,
         deny: denyList,
         allow_ip_literals: allowIpLiterals,