Send a JSON body when Enter chat starts a face room (#1098)

<!-- CURSOR_AGENT_PR_BODY_BEGIN -->
Written-by: Dev
Owner: Dev
Reviewer: Reviewer

Fixes #1085

## What changed
Enter chat calls `POST /v1/face-rooms/:id/start` with no body. On
https://social.botawaken.com that request is HTTP 500 `{ code:
"internal_error", message: "internal error" }` before auth, and the
waiting dialog shows that string. The same POST with `{}` reaches the
handler. Face-room POST, PUT, and PATCH calls that omit a body now send
`{}`.

Docs-not-needed: the face-room request body is not an architecture
change.

## Verification at the tip
Tip SHA: 5eee4ac

Fail-without-change: on the unbroken tip, `node --import
./test/resolve.mjs --test --test-name-pattern '#1085'
test/face-rooms.test.js` in plugins/social failed with message "internal
error" (code internal_error). After the callHttp change the same test
passes.

Ran: `TZ=UTC npm run verify` (exit 0). core lint and arch-docs OK;
plugins lint OK; client.js check OK; 10 patches apply; core equals
ds-bot + patches. core tests 1439 pass / 0 fail; social 476 pass / 0
fail (includes #1085); tree 125 pass / 0 fail; timeline 125 pass / 0
fail; .github/scripts 417 pass / 0 fail; interop 37 pass / 0 fail;
live-e2e 16 pass / 0 fail. After the commit, `node
core/scripts/check-arch-docs.mjs` reported OK (3 changed files) and
`node .github/scripts/changelog.mjs check` reported the fragments well
formed.

Not run: smoke (no core/index.js or src/host change). Desktop. A live
face room on Social (the production probe was unauthenticated: a
bodyless POST /start returned 500 internal error, and the same POST with
`{}` returned 401 and reached the handler).

## Self-review note
Implementer only. No Verdict. PASS and enqueue stay with the
coordinator.
Not enqueued.

<!-- CURSOR_AGENT_PR_BODY_END -->

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Co-authored-by: Cursor Agent <cursoragent@cursor.com>

Author: Birfy

changelog.d/1085-face-enter-internal-error.fixed.md

@@ -0,0 +1 @@
+Enter chat in a face-to-face room no longer shows "internal error" after the other person has joined. The start request sends an empty JSON body, which Bot Social accepts ([#1085](https://github.com/ThinkFlowLab/FlyBot/issues/1085)).

plugins/social/src/face-rooms.js

@@ -706,15 +706,21 @@ export function createFaceRoomApi({ server, token, fetch: fetchImpl = socialFetc
     let response
     let data
     const sentAt = Date.now()
+    // A POST or PUT with no body never reaches the handler on the deployed Bot Social
+    // (social.botawaken.com, 2026-10-25): it answers 500 "internal error" before auth.
+    // The same call with `{}` is an empty JSON body and the handler runs. Enter chat
+    // is POST /face-rooms/:id/start, which otherwise sends nothing (#1085).
+    const verb = String(method || 'GET').toUpperCase()
+    const payload = body === undefined && (verb === 'POST' || verb === 'PUT' || verb === 'PATCH') ? {} : body
     try {
       response = await fetchImpl(url, {
         method,
         headers: {
           authorization: `Bearer ${token}`,
           accept: 'application/json',
-          ...(body !== undefined ? { 'content-type': 'application/json' } : {}),
+          ...(payload !== undefined ? { 'content-type': 'application/json' } : {}),
         },
-        body: body !== undefined ? JSON.stringify(body) : undefined,
+        body: payload !== undefined ? JSON.stringify(payload) : undefined,
         signal,
       })
       const offset = serverClockOffset(response.headers?.get?.('date'), sentAt, Date.now())

plugins/social/test/face-rooms.test.js

@@ -439,6 +439,30 @@ test('REST join, poll, start, leave, and pending_approval send', async () => {
   assert.equal(left.status, 'closed')
 })
 
+test('#1085: Enter chat sends a JSON body, so a bodyless POST is not an internal error', async () => {
+  // social.botawaken.com (2026-10-25): POST /v1/face-rooms/:id/start with no body
+  // answers 500 { code: "internal_error", message: "internal error" } before auth.
+  // The same POST with `{}` reaches the handler. Enter chat is that POST.
+  const fetch = async (url, init) => {
+    assert.equal(String(url), 'https://s/v1/face-rooms/frm_1/start')
+    assert.equal(init.method, 'POST')
+    const raw = init.body
+    if (raw === undefined || raw === '') {
+      return new Response(JSON.stringify({ error: { code: 'internal_error', message: 'internal error' } }), { status: 500 })
+    }
+    assert.equal(init.headers['content-type'], 'application/json')
+    assert.equal(raw, '{}')
+    return new Response(JSON.stringify({
+      room_id: 'frm_1', status: 'open', members: [], events: [], event_cursor: 1,
+      started_at: '2026-10-25T00:00:00.000Z',
+    }), { status: 200 })
+  }
+  const api = createFaceRoomApi({ server: 'https://s', token: 'otk_test', fetch })
+  const started = await api.start('frm_1')
+  assert.equal(started.status, 'open')
+  assert.equal(started.roomId, 'frm_1')
+})
+
 test('failed join never includes members or events', () => {
   const err = mapFaceError({ error: { code: 'room_full', members: [{ handle: '@x' }], events: [1], room_id: 'frm_leak' } }, 409)
   assert.equal(err.message.includes('frm_leak'), false)