The global SSE broadcast called res.write() without checking the return
value, so a paused or backgrounded client would silently accumulate
every store event for every entity (tasks, missions, plugins, agents,
chat, ...) into res.outputData until the dashboard process OOMed.
Add a 4 MB writableLength threshold; when exceeded, tear down the
connection so the OS releases the buffer.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
