chore(types): fewer any casts; eslint warning ratchet 36 -> 29 (#210)

- Developer tools (send event, state event editor, room account data) and
  setMarkedUnread go through the typed helpers in utils/room and
  utils/accountData (new setRoomAccountData) instead of casting at the
  call site; sendStateEvent accepts a developer-chosen type string.
- SecretStorage passes the key description as the SDK's
  SecretStorageKeyDescription, CallEmbed replies with an IWidgetApiRequest,
  and fillMissingPowers writes through a Record instead of `as any`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/features/common-settings/developer-tools/StateEventEditor.tsx

@@ -31,6 +31,7 @@ import { usePowerLevels } from '../../../hooks/usePowerLevels';
 import { useTextAreaCodeEditor } from '../../../hooks/useTextAreaCodeEditor';
 import { useRoomCreators } from '../../../hooks/useRoomCreators';
 import { useRoomPermissions } from '../../../hooks/useRoomPermissions';
+import { sendStateEvent } from '../../../utils/room';
 
 const EDITOR_INTENT_SPACE_COUNT = 2;
 
@@ -59,7 +60,7 @@ function StateEventEdit({ type, stateKey, content, requestClose }: StateEventEdi
 
   const [submitState, submit] = useAsyncCallback<object, MatrixError, [object]>(
     useCallback(
-      (c) => mx.sendStateEvent(room.roomId, type as any, c, stateKey),
+      (c) => sendStateEvent(mx, room.roomId, type, c, stateKey),
       [mx, room, type, stateKey],
     ),
   );