Reverse proxies (OpenResty in front of minerva) buffer text/event-stream
by default, holding events until the response ends. An SSE stream never
ends, so the browser stays silent and WebUI pages never live-reload when
reached via app.doctate.de — while a direct minerva.lan:3000 client
(bypassing the proxy) works, explaining the desktop/Chromebook split.
Emit X-Accel-Buffering: no on the /events response so the proxy streams
it unbuffered; a direct client ignores the header. Return type widens
from Sse<..> to impl IntoResponse to carry the header tuple.
Regression guard: sse_integration asserts the header is present.
refs #12
Brummel
f957d9ddc6