Remote Control stops showing assistant output while the session continues running normally

## What happened

During an active session, the Remote Control client showed no assistant output for several minutes while the session was in fact running tool calls continuously. From the client it looked like the session had died.

The inbound direction kept working: four messages sent from the client during the silence all reached the session and were delivered to the assistant as mid-turn interjections. Only the outbound assistant→client direction stalled. The session never hung — it kept executing Bash tool calls throughout the silent period and responded normally once it produced its next message.

## Immediately before the silence

1. A `Skill` invocation whose result was a large skill body (several thousand tokens of instructions).
2. An `EnterWorktree` call that returned a tool *error* rather than a result (a path in another repository, correctly rejected).

I can't tell which of these — if either — is implicated, and would rather not guess than send you down a wrong path.

## Expected

Assistant output continues to reach the Remote Control client, or the client surfaces that the stream has stalled.

## Actual

Silence indistinguishable from a dead session, while the session is healthy and working.

## Impact

Low severity, but the failure mode is misleading in the direction that matters: from the client you cannot tell "still working" from "crashed", so the reflex is to interrupt work that was fine.

## Environment

- Claude Code 2.1.233
- Linux 6.8.0-137-generic
- Model: Opus 5
- Session id: `session_014ZMePF7MmJH1MnzSy2VM3E` (2026-08-17, ~08:00–09:15 CEST) — for correlating with server-side logs; no transcript is attached to this issue deliberately.

No source file or test is named. Start by correlating the supplied session ID with server-side logs, comparing the outbound stream around the large Skill result and rejected EnterWorktree call with the still-working inbound path. Done means assistant output continues to reach Remote Control, or the client clearly reports that the stream has stalled.

Written by the indexing model from the issue text.