refactor(types): typed send helpers replace 16 as any casts (#210)

- sendRoomMessage (composer's fire-and-forget sends: text, location, voice,
  files, GIFs) and sendRoomEvent (polls, poll responses/ends, forwards,
  reactions, edits) in utils/room.ts carry the one cast each needs
  (`keyof TimelineEvents` / `RoomMessageEventContent`, no `any`).
- sendRoomMessage also swallows the rejected promise: a failed send already
  shows on the local echo (Failed to send + Retry, or the consent prompt), so
  it no longer surfaces as an unhandled error in the console.
- getAccountData narrows to `keyof AccountDataEvents`; ForwardMessageDialog's
  guard now narrows `contentToSend` itself (same behaviour).
- `as any` 39 → 23; eslint warnings 46 → 36, ratchet tightened to 36.

Verified in Chromium on a local Synapse: a text message, a quick reaction and
an edit all reach the server with the right content; a consent-blocked send
no longer logs an unhandled MatrixError. 1219 unit tests pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/room/thread/ThreadTimeline.tsx

@@ -67,6 +67,7 @@ import {
   getMemberName,
   getReactionContent,
   reactionOrEditEvent,
+  sendRoomEvent,
 } from '../../../utils/room';
 import { useSetting } from '../../../state/hooks/settings';
 import { MessageLayout, settingsAtom } from '../../../state/settings';
@@ -576,12 +577,12 @@ export function ThreadTimeline({ room, thread, editor }: ThreadTimelineProps) {
         shortcode ||
         (reactions.find(eventWithShortcode)?.getContent().shortcode as string | undefined);
       tick('reaction', hapticFeedback);
-      mx.sendEvent(
+      sendRoomEvent(
+        mx,
         room.roomId,
         // A reaction on the root is a main-timeline event, not a thread reply.
         isRoot ? null : thread.id,
-        // eslint-disable-next-line @typescript-eslint/no-explicit-any
-        MessageEvent.Reaction as any,
+        MessageEvent.Reaction,
         getReactionContent(targetEventId, key, rShortcode),
       );
     },