feat(FN-2009): show waiting and thinking states during chat streaming

- Render streaming assistant bubbles in ChatView and QuickChatFAB as soon as streaming starts
- Show "Connecting…" before text arrives and switch to "Thinking…" when thinking output is present
- Render streaming thinking content in a collapsible details block in QuickChatFAB to match ChatView behavior
- Add muted italic waiting-state styles for chat and quick chat message content
- Add ChatView streaming state tests for waiting and thinking pre-text scenarios

packages/dashboard/app/components/ChatView.tsx

@@ -992,7 +992,7 @@ export function ChatView({ projectId, addToast }: ChatViewProps) {
                   <div className="chat-message-time">{formatRelativeTime(message.createdAt)}</div>
                 </div>
               ))}
-              {isStreaming && streamingText && (
+              {isStreaming && (
                 <div className="chat-message chat-message--assistant chat-message--streaming">
                   <div className="chat-message-avatar">
                     <Bot size={14} />
@@ -1002,7 +1002,13 @@ export function ChatView({ projectId, addToast }: ChatViewProps) {
                       return modelTag ? <span className="chat-model-tag">{modelTag}</span> : null;
                     })()}
                   </div>
-                  <div className="chat-message-content">{renderMessageContent(streamingText)}</div>
+                  {streamingText ? (
+                    <div className="chat-message-content">{renderMessageContent(streamingText)}</div>
+                  ) : (
+                    <div className="chat-message-content chat-message-content--waiting">
+                      {streamingThinking ? "Thinking…" : "Connecting…"}
+                    </div>
+                  )}
                   {streamingThinking && (
                     <details className="chat-message-thinking">
                       <summary>Thinking</summary>