* feat(terminal): broadcast output to every viewer instead of one shared queue
TerminalSession.output was a single queue.Queue read destructively by the SSE
handler. Two tabs/windows viewing the SAME session each open their own
EventSource, so two _handle_terminal_output handlers competed on that one queue:
every PTY chunk was delivered to exactly one of them. Each tab saw a disjoint
half of the byte stream, and only one ever received terminal_closed.
Output now fans out, mirroring StreamChannel/SessionChannel: each SSE consumer
subscribe()s its own queue (seeded with a bounded backlog so a first/late attach
still replays the recent scrollback, preserving the old buffer-until-first-
consumer behaviour), and put_output broadcasts to all subscribers. A slow
viewer's queue drops its own oldest chunk (drop-oldest, isolated per subscriber)
so one lagging tab can't starve another. The handler unsubscribes in a finally
so the subscriber list can't grow.
Stacked on the terminal fd-leak fix (same file).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* fix: cover terminal broadcast lifecycle
* fix: serialize terminal subscriber fanout
* test: cover terminal unsubscribe publication race
* restore timing-flaky pytest.skip on test_terminal_survives_short_lived_request_thread (keep API-updated body); changelog #5836
---------
Co-authored-by: ai-ag2026 <261867348+ai-ag2026@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: nesquena-hermes <agent@nesquena-hermes>
