test: add suites for 8 simple state reducers + msgContent (+50)

Via subagent, all verified, no bugs:
- state/toast (7), room-list/roomList (6), inviteList (6), room-list/utils
  compareRoomsEqual (6), backupRestore (6), callEmbed dispose-on-replace (6),
  closedNavCategories factory + makeNavCategoryId (8).
- features/room/msgContent (5): getAudioMsgContent/getFileMsgContent incl.
  encrypted (content.file) vs plain (content.url) branch.

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

src/app/features/room/msgContent.test.ts

@@ -0,0 +1,76 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { MsgType } from 'matrix-js-sdk';
+import { EncryptedAttachmentInfo } from 'browser-encrypt-attachment';
+import { getAudioMsgContent, getFileMsgContent } from './msgContent';
+import { TUploadItem } from '../../state/room/roomInputDrafts';
+
+// Pure builders getAudioMsgContent / getFileMsgContent: msgtype/body/filename/info
+// shape plus the encInfo branch (content.file w/ url vs plain content.url). The
+// image/video builders need a DOM + MatrixClient and are not covered here.
+
+const MXC = 'mxc://example.org/abc';
+
+const makeItem = (encInfo?: EncryptedAttachmentInfo): TUploadItem => {
+  const file = { name: 'sound.ogg', type: 'audio/ogg', size: 4096 };
+  return {
+    file,
+    originalFile: file,
+    metadata: { markedAsSpoiler: false },
+    encInfo,
+  } as unknown as TUploadItem;
+};
+
+const fakeEncInfo = (): EncryptedAttachmentInfo =>
+  ({
+    v: 'v2',
+    key: { alg: 'A256CTR' },
+    iv: 'iv',
+    hashes: { sha256: 'h' },
+  }) as unknown as EncryptedAttachmentInfo;
+
+test('getAudioMsgContent builds an unencrypted audio message', () => {
+  const content = getAudioMsgContent(makeItem(), MXC);
+  assert.equal(content.msgtype, MsgType.Audio);
+  assert.equal(content.body, 'sound.ogg');
+  assert.equal(content.filename, 'sound.ogg');
+  assert.deepEqual(content.info, { mimetype: 'audio/ogg', size: 4096 });
+  assert.equal(content.url, MXC);
+  assert.equal(content.file, undefined);
+});
+
+test('getAudioMsgContent uses content.file with url when encInfo is present', () => {
+  const enc = fakeEncInfo();
+  const content = getAudioMsgContent(makeItem(enc), MXC);
+  assert.equal(content.url, undefined);
+  assert.deepEqual(content.file, { ...enc, url: MXC });
+});
+
+test('getFileMsgContent builds an unencrypted file message', () => {
+  const content = getFileMsgContent(makeItem(), MXC);
+  assert.equal(content.msgtype, MsgType.File);
+  assert.equal(content.body, 'sound.ogg');
+  assert.equal(content.filename, 'sound.ogg');
+  assert.deepEqual(content.info, { mimetype: 'audio/ogg', size: 4096 });
+  assert.equal(content.url, MXC);
+  assert.equal(content.file, undefined);
+});
+
+test('getFileMsgContent uses content.file with url when encInfo is present', () => {
+  const enc = fakeEncInfo();
+  const content = getFileMsgContent(makeItem(enc), MXC);
+  assert.equal(content.url, undefined);
+  assert.deepEqual(content.file, { ...enc, url: MXC });
+});
+
+test('info mirrors the file mimetype and size', () => {
+  const item = {
+    file: { name: 'doc.pdf', type: 'application/pdf', size: 12 },
+    originalFile: { name: 'doc.pdf', type: 'application/pdf', size: 12 },
+    metadata: { markedAsSpoiler: false },
+    encInfo: undefined,
+  } as unknown as TUploadItem;
+  const content = getFileMsgContent(item, MXC);
+  assert.deepEqual(content.info, { mimetype: 'application/pdf', size: 12 });
+  assert.equal(content.body, 'doc.pdf');
+});