Empty prompt bubble renders below skill pill on skill-only invocations

[jeonghun-jj-lee]

Important

Problem — When a user invokes a skill with no message body (e.g. /tdd with no additional text), a small empty gray rectangle renders below the skill pill. The blob is the user-message-text prompt bubble mounting unconditionally with its padding and background visible despite having no text content.

Scope — in: the UserMessageDisplay render path in session-ui's message-part.tsx and the identical code in the opencode overlay. out: assistant-side empty-text filtering (already handled by renderable()), CSS-only fixes (fragile with SolidJS comment markers vs :empty).

Acceptance Criteria

• Invoking a skill with no body text (e.g. /tdd) renders the skill pill without an empty prompt bubble below it
• Invoking a skill WITH body text still renders both the skill pill and the text bubble
• UserMessageComments still render when present on a skill-only message (guard includes comments check)

Key Decisions

The [data-slot="user-message-text"] div should be wrapped in <Show when={text() || messageComments().length > 0}> rather than just <Show when={text()}>, so that inline comments attached to a skill-only message are not accidentally hidden.

Constraints & Invariants

• The fix must be applied in both the amicode overlay (packages/app-bundle/overlay/packages/session-ui/) and the opencode source (packages/session-ui/)
• renderable() is not called on the user-message path and should not need to be — the conditional belongs at the render site

Prior Art

• UserMessageDisplay component in session-ui message-part.tsx (around line 1823)
• renderable() function in the same file (line 753) — handles the equivalent filter on the assistant side
• last-prompt-bubble.test.ts — already models skill-only messages for the floating bubble feature, but does not cover inline rendering