fix: terminal reconnect typing and reset functionality

Frontend:
- Fix term.onData to use wsRef.current instead of captured ws variable
- Fix fitTerminal to use wsRef.current for resize messages
- Fix sendData callback to use wsRef.current
- This fixes 'cannot type' after WebSocket reconnect

Backend:
- Add SessionRef class for mutable session reference
- Update _read_loop and _write_loop to use SessionRef
- Reset now updates session_ref.session instead of returning
- This keeps the WebSocket alive after reset instead of closing it

apps/api/src/api/terminal.py

@@ -15,6 +15,13 @@ router = APIRouter()
 logger = logging.getLogger(__name__)
 
 
+class SessionRef:
+    """Mutable reference to a terminal session, allowing updates during reset."""
+
+    def __init__(self, session):
+        self.session = session
+
+
 @router.websocket(
     "/ws/tool-instances/{instance_id}/terminal",
 )
@@ -86,9 +93,12 @@ async def terminal_websocket(
         # Send connected status
         await websocket.send_json({"type": "status", "status": "connected"})
 
+        # Use mutable session reference so loops can survive reset
+        session_ref = SessionRef(session)
+
         # Start I/O loops and heartbeat
-        read_task = asyncio.create_task(_read_loop(session, websocket))
-        write_task = asyncio.create_task(_write_loop(session, websocket, instance_id))
+        read_task = asyncio.create_task(_read_loop(session_ref, websocket))
+        write_task = asyncio.create_task(_write_loop(session_ref, websocket, instance_id))
         heartbeat_task = asyncio.create_task(_heartbeat_loop(websocket))
 
         # Wait for either task to complete (indicating disconnect or error)
@@ -114,10 +124,14 @@ async def terminal_websocket(
             pass
 
 
-async def _read_loop(session, websocket) -> None:
+async def _read_loop(session_ref: SessionRef, websocket) -> None:
     """Read output from the container and send to WebSocket."""
     try:
-        while session.is_alive() and not session._closed:
+        while True:
+            session = session_ref.session
+            if not session.is_alive() or session._closed:
+                await asyncio.sleep(0.1)
+                continue
             data = await session.read_output()
             if data:
                 try:
@@ -130,10 +144,14 @@ async def _read_loop(session, websocket) -> None:
         pass
 
 
-async def _write_loop(session, websocket, instance_id: str) -> None:
+async def _write_loop(session_ref: SessionRef, websocket, instance_id: str) -> None:
     """Read input from WebSocket and send to container."""
     try:
-        while session.is_alive() and not session._closed:
+        while True:
+            session = session_ref.session
+            if not session.is_alive() or session._closed:
+                await asyncio.sleep(0.1)
+                continue
             message = await websocket.receive()
             if message["type"] == "websocket.receive":
                 if "bytes" in message:
@@ -163,14 +181,15 @@ async def _write_loop(session, websocket, instance_id: str) -> None:
                                     session.container_id,
                                 )
                                 
+                                # Update the mutable session reference so read_loop uses the new session
+                                session_ref.session = new_session
+                                
                                 # Attach to new session
                                 await terminal_manager.attach_websocket(new_session, websocket)
                                 await websocket.send_json({"type": "status", "status": "connected"})
                                 
-                                # Update session reference and restart loops
-                                # Note: This will cause the current loops to exit
-                                # The WebSocket handler will create new ones
-                                return
+                                # Continue the loop with the new session
+                                continue
                                 
                         except json.JSONDecodeError:
                             pass

apps/web/src/components/terminal.tsx

@@ -225,8 +225,9 @@ export const TerminalComponent: React.FC<TerminalProps> = ({
       if (cols !== oldCols || rows !== oldRows) {
         termRef.current.refresh(0, rows - 1);
       }
-      if (ws.readyState === WebSocket.OPEN) {
-        ws.send(JSON.stringify({ type: "resize", cols, rows }));
+      const currentWs = wsRef.current;
+      if (currentWs?.readyState === WebSocket.OPEN) {
+        currentWs.send(JSON.stringify({ type: "resize", cols, rows }));
       }
     };
 
@@ -244,20 +245,21 @@ export const TerminalComponent: React.FC<TerminalProps> = ({
 
     // Handle terminal input
     term.onData((data) => {
-      if (ws.readyState !== WebSocket.OPEN) return;
+      const currentWs = wsRef.current;
+      if (currentWs?.readyState !== WebSocket.OPEN) return;
 
       // Apply active modifier to single-character input
       const modifier = activeModifierRef.current;
       if (modifier && data.length === 1) {
         const modified = applyModifierToChar(data, modifier);
         if (modified) {
-          ws.send(modified);
+          currentWs.send(modified);
           onModifierChange?.(null);
           return;
         }
       }
 
-      ws.send(data);
+      currentWs.send(data);
     });
 
     // Handle container resize with ResizeObserver for accurate dimension tracking
@@ -302,8 +304,9 @@ export const TerminalComponent: React.FC<TerminalProps> = ({
     // Notify parent about terminal readiness
     if (onTerminalReadyRef.current) {
       const sendData = (data: string) => {
-        if (ws.readyState === WebSocket.OPEN) {
-          ws.send(data);
+        const currentWs = wsRef.current;
+        if (currentWs?.readyState === WebSocket.OPEN) {
+          currentWs.send(data);
         }
       };
       const focusInput = () => {