Add prominent mobile menu instruction at top of page

Added a visible callout box explaining where to find the hamburger
menu (top-left corner) for mobile users.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.py

@@ -65,6 +65,15 @@ if "messages" not in st.session_state:
 st.markdown("<h1 style='text-align: center; color: #333;'>Practice Difficult Conversations</h1>", unsafe_allow_html=True)
 st.markdown("<p style='text-align: center; font-size: 18px; color: #555; margin-bottom: 1em;'>With Your Attachment Style Front and Center!</p>", unsafe_allow_html=True)
 
+# Mobile-friendly setup prompt
+if not st.session_state.setup_complete:
+    st.markdown("""
+    <div style='background-color: #e8f4f8; padding: 15px; border-radius: 10px; margin-bottom: 20px; text-align: center;'>
+        <strong>📱 On mobile?</strong> Tap the <strong>☰ menu icon</strong> in the <strong>top-left corner</strong> to open the setup form.<br>
+        <strong>💻 On desktop?</strong> Use the sidebar on the left.
+    </div>
+    """, unsafe_allow_html=True)
+
 # Welcome text and instructions
 if not st.session_state.setup_complete:
     st.markdown("""