fix: Replace deprecated Plotly titlefont with title.font

app.py

@@ -388,9 +388,9 @@ def build_coherence_timeline(coherence_history: List[float],
     fig.update_layout(
         title="Coherence & Tension Evolution",
         xaxis=dict(title="Message Index", gridcolor="rgba(200, 200, 255, 0.1)"),
-        yaxis=dict(title="Coherence (Γ)", titlefont=dict(color="#06b6d4"),
+        yaxis=dict(title=dict(text="Coherence (Γ)", font=dict(color="#06b6d4")),
                   tickfont=dict(color="#06b6d4"), gridcolor="rgba(6, 182, 212, 0.1)"),
-        yaxis2=dict(title="Tension", titlefont=dict(color="#ef4444"),
+        yaxis2=dict(title=dict(text="Tension", font=dict(color="#ef4444")),
                    tickfont=dict(color="#ef4444"), anchor="x", overlaying="y"),
         hovermode='x unified',
         height=400,