refactor(compute): remove SPICE WebSocket console support

Remove all SPICE WebSocket-related code due to frontend dependency issues
with spice-html5 library (missing RSAKey/BigInteger implementations).

Changes:
- Remove start_spice_websocket_console() from BaseNode
- Remove SPICE WebSocket endpoints from QEMU and Docker compute APIs
- Remove SPICE WebSocket proxy endpoint from controller API
- Remove WebSocket subprotocol handling from authentication layers
- Remove SPICE documentation

The SPICE console type remains functional for direct connections,
but WebSocket proxy support has been removed.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

gns3server/compute/base_node.py

@@ -611,76 +611,6 @@ class BaseNode:
         vnc_writer.close()
         await vnc_writer.wait_closed()
 
-    async def start_spice_websocket_console(self, websocket):
-        """
-        Connect to SPICE console using WebSocket.
-
-        :param websocket: FastAPI WebSocket object
-        """
-
-        log.info(
-            f"New client {websocket.client.host}:{websocket.client.port} has connected to compute "
-            f"SPICE console WebSocket"
-        )
-
-        if self.status != "started":
-            await websocket.close(code=1000)
-            raise NodeError(f"Node {self.name} is not started")
-        if self._console_type not in ("spice", "spice+agent"):
-            await websocket.close(code=1000)
-            raise NodeError(f"Node {self.name} console type is not SPICE")
-
-        try:
-            spice_reader, spice_writer = await asyncio.open_connection(
-                self._manager.port_manager.console_host,
-                self.console  # SPICE port
-            )
-            log.info(f"Connected to SPICE server {self._manager.port_manager.console_host}:{self.console}")
-        except ConnectionError as e:
-            await websocket.close(code=1000)
-            raise NodeError(f"Cannot connect to node {self.name} SPICE server: {e}")
-
-        async def ws_forward(spice_writer):
-            # Browser → SPICE: Forward binary WebSocket data to SPICE server
-            try:
-                while True:
-                    data = await websocket.receive_bytes()
-                    if data:
-                        spice_writer.write(data)
-                        await spice_writer.drain()
-            except WebSocketDisconnect:
-                log.info(
-                    f"Client {websocket.client.host}:{websocket.client.port} has disconnected from compute "
-                    f"SPICE console WebSocket"
-                )
-
-        async def spice_forward(spice_reader):
-            # SPICE → Browser: Forward SPICE data to WebSocket
-            try:
-                while not spice_reader.at_eof():
-                    data = await spice_reader.read(65536)  # Larger buffer for SPICE data
-                    if data:
-                        await websocket.send_bytes(data)
-            except Exception as e:
-                log.warning(f"Exception while forwarding SPICE data to WebSocket: {e}")
-
-        # Keep forwarding WebSocket data in both directions
-        if sys.version_info >= (3, 11, 0):
-            # Starting with Python 3.11, passing coroutine objects to wait() directly is forbidden.
-            aws = [asyncio.create_task(ws_forward(spice_writer)), asyncio.create_task(spice_forward(spice_reader))]
-        else:
-            aws = [ws_forward(spice_writer), spice_forward(spice_reader)]
-
-        done, pending = await asyncio.wait(aws, return_when=asyncio.FIRST_COMPLETED)
-        for task in done:
-            if task.exception():
-                log.warning(f"Exception while forwarding WebSocket data to SPICE server: {task.exception()}")
-        for task in pending:
-            task.cancel()
-
-        spice_writer.close()
-        await spice_writer.wait_closed()
-
     @property
     def aux(self):
         """