Chat: accept attachments in room messages (#473)

ddiff --git a/server/rooms/files.js b/server/rooms/files.js
iindex 1715ce9..3baed65 100644
---- a/server/rooms/files.js
++++ b/server/rooms/files.js
@@@ -40,10 +40,19 @@ function cleanOne(file, index, reader = null) {
  /** The files a message may carry (at most MAX_FILES), or [] when it has none. */
  function cleanFiles(files, reader = null) {
      if (!Array.isArray(files) || !files.length) return [];
--    if (files.length > MAX_FILES) throw new RoomError(413, 'rooms.files_too_many', `At most ${MAX_FILES} files can go with a message`);
++    if (files.length > MAX_FILES) {
++        const { RoomError } = require('./rooms');
++        throw new RoomError(413, 'rooms.files_too_many', `At most ${MAX_FILES} files can go with a message`);
++    }
      return files.map((f, i) => cleanOne(f, i, reader));
  }
  
++/** The message API calls these attachments; the AI pipeline keeps its historical `files` name. */
++function attachmentsFromBody(body) {
++    if (!body || typeof body !== 'object') return [];
++    return Array.isArray(body.attachments) ? body.attachments : (Array.isArray(body.files) ? body.files : []);
++}
++
  /** The files stored on a message row (jsonb comes back as an array; a text column is tolerated too). */
  function filesOf(message) {
      if (!message) return [];
@@@ -52,4 +61,4 @@ function filesOf(message) {
      return Array.isArray(files) ? files : [];
  }
  
--module.exports = { cleanFiles, filesOf, MAX_FILES };
++module.exports = { cleanFiles, filesOf, attachmentsFromBody, MAX_FILES };
ddiff --git a/server/rooms/routes.js b/server/rooms/routes.js
iindex da0198b..8bffab3 100644
---- a/server/rooms/routes.js
++++ b/server/rooms/routes.js
@@@ -211,7 +211,7 @@ router.post('/:slug/messages', requireAuth, postLimit, async (req, res) => {
      try {
          const message = await rooms.post(room, req.user, req.body && req.body.message, {
              timezone: req.body && req.body.timezone,
--            files: req.body && req.body.files,
++            files: require('./files').attachmentsFromBody(req.body),
              reply_to_id: req.body && req.body.reply_to_id,
          });
          chatServer().broadcastToRoom(room.id, { type: 'room_message', room: room.slug, message });
ddiff --git a/test/room-attachments.test.js b/test/room-attachments.test.js
nnew file mode 100644
iindex 0000000..ad6010e
---- /dev/null
++++ b/test/room-attachments.test.js
@@@ -0,0 +1,14 @@
++'use strict';
++const assert = require('node:assert/strict');
++const { suite } = require('./helpers');
++const t = suite('room attachments');
++const files = require('../server/rooms/files');
++
++t('room message attachments accept the public field name and enforce the ten-file limit', () => {
++    assert.deepEqual(files.attachmentsFromBody({ attachments: [{ id: 'a' }] }), [{ id: 'a' }]);
++    assert.deepEqual(files.attachmentsFromBody({ files: [{ id: 'b' }] }), [{ id: 'b' }]);
++    assert.deepEqual(files.attachmentsFromBody({ attachments: 'invalid', files: [{ id: 'b' }] }), [{ id: 'b' }]);
++    assert.throws(() => files.cleanFiles(Array(11).fill({ id: 'med_01ARZ3NDEKTSV4RRFFQ69G5FAV' })), (err) => err.code === 'rooms.files_too_many' && err.status === 413);
++});
++
++t.run();