CODEX PROMPT UI

# Codex Prompt: App.jsx UI Wiring for Ghost Variables + Golden Response

**Target file (modify only this):**
- `prompt-lab-extension/src/App.jsx`

**Do NOT modify:** any hooks, utilities, schema files, or other components.

## Context

Two data-layer features have been implemented and verified:

1. **Ghost Variables** — `isGhostVar()` and `resolveGhostVars()` exist in `promptUtils.js`.
   The `loadEntry()` hook in `usePromptEditor.js` already resolves ghost vars and
   pre-fills `varVals` with their values. The var form modal in App.jsx (line 613)
   currently renders all variables identically — ghost vars need a visual indicator.

2. **Golden Response** — `pinGoldenResponse()` and `clearGoldenResponse()` exist on
   the library hook. `ngramSimilarity()` exists in `promptUtils.js`. `wordDiff()` is
   already imported and used. The prompt schema now includes `goldenResponse` on
   library entries. The UI needs pin buttons and a comparison panel.

## Current App.jsx Structure (relevant sections)

**Imports (line 1–18):**