console: forward client terminal size over the console WebSocket

The docker_exec console defaults its exec PTY to 511x10000 (the no-NAWS
default that keeps the IOS-XR pager quiet for netmiko). A CPR-answering
client (xterm.js) on top of that tall canvas makes prompt_toolkit-based
CLIs (SR Linux sr_cli) re-emit their accumulated output on every
incremental render: ~145 KB instead of ~60 KB per command, visible in
the WebUI as full-screen clear/redraw flicker.

Let WebSocket console clients propagate their real terminal geometry:
binary frames {"cols": N, "rows": M} alongside text frames carrying
terminal data. The controller forwards binary frames (previously only
text was forwarded), and the compute side turns them into a NAWS
subnegotiation for telnet-based consoles (docker_exec included) or an
asyncssh pty size change for SSH consoles.

The docker_exec console restores the tall 511x10000 default when its
last client disconnects, so a later non-NAWS client (netmiko, bare
telnet) connecting to the still-live exec doesn't inherit a browser
geometry and hit PTY-window paging again.

gns3server/api/routes/controller/nodes.py

@@ -694,13 +694,19 @@ async def ws_console(
     async def ws_receive(ws_console_compute):
         """
         Receive WebSocket data from client and forward to compute console WebSocket.
+        Text frames carry terminal data; binary frames carry client control
+        messages (e.g. terminal size), forwarded as-is.
         """
 
         try:
             while True:
-                data = await websocket.receive_text()
-                if data:
-                    await ws_console_compute.send_str(data)
+                msg = await websocket.receive()
+                if msg["type"] == "websocket.disconnect":
+                    break
+                if "text" in msg and msg["text"]:
+                    await ws_console_compute.send_str(msg["text"])
+                elif "bytes" in msg and msg["bytes"]:
+                    await ws_console_compute.send_bytes(msg["bytes"])
         except WebSocketDisconnect:
             await ws_console_compute.close()
             log.info(