Review round 4 of #78: /api/android and /api/titles re-raise frame_android's
FrameError as Failure(str(e)), which dropped frame_link_failed, so their
connection failures were still reported after the status poll's first one.
Both now raise ... from e, and diagnostic() follows __cause__
(frame_telemetry.link_failed). server.ssh() judges a link failure on ssh's
stderr only, never the command's stdout.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>