`_stream_frames` (the mobile JPEG fallback) retried forever: on `TimeoutError`
it logged and `continue`d, and on `captured is None` it just `continue`d. A
phone unplugged mid-stream, or a dead adb bridge, makes every capture fail at
once, so the loop spun at the frame interval indefinitely — a warning per
iteration, a log flood, and a canvas frozen on the last frame with nothing ever
sent to explain it.
The desktop sibling `desktop/stream.py::_stream_loop` already counts consecutive
misses, warns once, and after 30 sends an error frame and breaks. This mirrors
that: timeouts and `None` both count as misses, the first one is logged once,
and at `_CAPTURE_MISS_LIMIT` (30) the stream sends the
`{"type": "error", "message": ...}` frame the rest of this router already uses
and returns. A successful frame resets the streak, so an occasional dropped
frame still does not tear the stream down.
Folding the timeout branch into the shared counter also removes the
per-iteration warning flood.
