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/message/ForwardMessageDialog.tsx

@@ -36,7 +36,12 @@ import { mxcUrlToHttp } from '../../../utils/matrix';
 import { RoomAvatar, RoomIcon } from '../../../components/room-avatar';
 import { UserAvatar } from '../../../components/user-avatar';
 import { ThumbnailContent } from '../../../components/message/content/ThumbnailContent';
-import { getMemberAvatarMxc, getMemberName, trimReplyFromBody } from '../../../utils/room';
+import {
+  getMemberAvatarMxc,
+  getMemberName,
+  sendRoomEvent,
+  trimReplyFromBody,
+} from '../../../utils/room';
 import { nameInitials } from '../../../utils/common';
 import {
   recentForwardTargetsAtom,
@@ -349,12 +354,12 @@ export function ForwardMessageDialog({ mEvent, onClose }: Props) {
       // content; unencrypted ones get the plaintext version, or fail outright if
       // that couldn't be built — never fall back to sending the encrypted `file`.
       const contentToSend = fwdContent.file && !destEncrypted ? plaintextContent : fwdContent;
-      if (fwdContent.file && !destEncrypted && !contentToSend) {
+      // Only undefined when a plaintext copy was needed and couldn't be built.
+      if (!contentToSend) {
         return Promise.reject(new Error(plaintextContentError));
       }
-      // threadId-aware overload (P3-8): explicit null = send to the main timeline.
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      const sendForward = () => mx.sendEvent(id, null, mEvent.getType() as any, contentToSend);
+      // Explicit null thread = send to the main timeline.
+      const sendForward = () => sendRoomEvent(mx, id, null, mEvent.getType(), contentToSend);
       // Send the optional comment first so it reads as a note above the
       // forwarded content. The room counts as failed if either send rejects.
       // Track rooms whose comment already landed so a retry (after the FORWARD