The IDE backend is uploaded by streaming it into `gzip -dc > file` on the
host. When that command exits early (no gzip, a folder it cannot write, a
full disk), it stops reading: once the channel window (about 2 MB) is
used up, the next write waited for window space forever, so Remote
Development stayed on "Installing the IDE backend on the host…" at a few
percent and never showed the host's error. Each write, and closing the
input, now races the command's exit; an early exit ends the upload with
the command's status and stderr.
Refs #1330
Remote windows get a Ports tool window: forward localhost:<port> of the remote host to this machine (same port when free here), with Open in Browser / Copy / Stop. Forwarded ports are remembered per host and folder and forwarded again on reconnect. Tunnels reuse the window's SSH session (ide_ssh::Tunnel can prefer a local port) and close with the connection.
Closes#819
l0ng-ai