Create SessionChatPanel React component

## Task Create a reusable React chat panel component for support sessions that works in both operator and guest contexts. ## Component: SessionChatPanel ```jsx // app/javascript/components/remote_support/SessionChatPanel.jsx export default function SessionChatPanel({ sessionId, participantType, // 'operator' | 'guest' participantName, token, // guest link token (for guests) initialMessages, isCollapsed, onToggle, disabled, // true when session ended }) { // State: messages, inputValue, sending, connectionStatus // Subscribe to real-time updates // Handle message sending // Auto-scroll behavior } ``` ## Features 1. **Message List**: Scrollable list with sender alignment (own messages right, others left) 2. **Input Area**: Textarea with send button, Enter to send, Shift+Enter for newline 3. **Collapse Toggle**: Button to minimize/expand panel 4. **Connection Status**: Badge showing connected/disconnected state 5. **Empty State**: Friendly message when no chat history ## Transport Abstraction Create a hook `useSupportSessionChat` that abstracts the transport: - For operators: uses NATS subscription via existing chat_service pattern - For guests: uses ActionCable subscription ## Styling - Match existing DaisyUI chat bubble styling from `ChatRoom.jsx` - Responsive width (fixed width panel on desktop, full width on mobile) - Smooth collapse animation ## Files to Create - `app/javascript/components/remote_support/SessionChatPanel.jsx` - `app/javascript/components/remote_support/useSupportSessionChat.js` - `spec/javascript/components/remote_support/SessionChatPanel.spec.jsx`