[BUG] VS Code extension: a long slash-command prompt renders as a full-panel expanded card that covers the conversation

Bug Description

In the VS Code Claude Code extension, submitting a very long prompt via a slash command (in my case /goal with ~30 lines across several paragraphs) causes the submitted user message to render as a large "expanded message" card — with its own CLAUDE CODE header bar (expand and close controls) — that occupies the entire extension panel. The assistant is clearly working underneath (the spinner shows "Deliberating…"), but the response is hidden because the expanded prompt card persists over the full panel and doesn't collapse on its own. The "Queue another message…" input stays visible at the bottom.

Net effect: the whole panel is taken over by a static view of the prompt I just sent, blocking the assistant's reply.

Steps to Reproduce

1. Open the Claude Code panel in VS Code.
2. Invoke a slash command with a long, multi-paragraph argument (e.g. /goal followed by ~25–40 lines).
3. Submit.

Expected

The submitted prompt collapses to a compact bubble / scrolls with the transcript, and the streaming response is visible.

Actual

The submitted prompt fills a full-panel expanded card with a CLAUDE CODE title bar; the response area is hidden behind it. Approximate layout:

┌─────────────────────────────────────┐
│ CLAUDE CODE                  ⛶    ✕ │
│ <title truncated>            ⟲    ＋ │
│ ┌─────────────────────────────────┐ │
│ │ /goal <long multi-paragraph …>  │ │ ← fills whole panel
│ └─────────────────────────────────┘ │
│ ✳ Deliberating…                     │ ← live reply hidden behind card
│ [ Queue another message…          ] │
└─────────────────────────────────────┘

Environment

• Claude Code for VS Code — v2.1.183 (win32-x64)
• OS: Windows 11
• Editor: VS Code

(Screenshot available but omitted — it contained private project content.)