Fix remaining bumplot issues

Fixed three critical issues:

1. CURVES EXTENDING BEYOND DISPLAYED TOKENS:
   - Added clamping to max_vocab_display in rank assignment
   - Particles with tokens beyond max rank are now capped at the max visible rank
   - Prevents curves from going to non-existent rank 9 when only showing 8 ranks

2. COLORBAR POSITION:
   - Moved to x=0.88 (was 0.90, then 0.86)
   - Now has proper small gap from main figure

3. ALPHA TRANSPARENCY:
   - Reduced to 0.1 for clear visibility of overlapping paths
   - Using explicit line.set_alpha() for better rendering
   - Transparency now clearly visible in dense areas

The bumplot now correctly shows all particles within the visible
rank range, with proper transparency and layout spacing.

Author: jeremymanning

code/quantum_conversations/custom_bumplot.py

@@ -21,7 +21,7 @@ def create_custom_bumplot(
     metadata: Dict,
     ax: plt.Axes,
     colormap: str = 'RdYlGn',
-    alpha: float = 0.2,  # Lower alpha for better transparency visibility
+    alpha: float = 0.1,  # Very low alpha to test transparency
     linewidth: float = 2.5,
     curve_force: float = 0.3
 ) -> None:
@@ -100,9 +100,11 @@ def create_custom_bumplot(
                         y_segment = np.concatenate([y_segment, y_overlap])
 
                     # Plot this segment with explicit alpha
-                    ax.plot(x_segment, y_segment, color=color, alpha=alpha,
-                           linewidth=linewidth, solid_capstyle='round',
-                           solid_joinstyle='round', zorder=100, rasterized=False)  # Below labels
+                    # Force matplotlib to use alpha blending
+                    line, = ax.plot(x_segment, y_segment, color=color,
+                                   linewidth=linewidth, solid_capstyle='round',
+                                   solid_joinstyle='round', zorder=100)
+                    line.set_alpha(alpha)  # Explicitly set alpha on line object
 
             except Exception as e:
                 # Fallback to linear segments

code/quantum_conversations/visualizer.py

@@ -589,6 +589,9 @@ def _prepare_bumplot_data(
                     token_id = particle.tokens[t]
                     # Use the rank map to ensure consistency
                     rank = position_ranks[t].get(token_id, max_vocab_display + 1)
+                    # Clamp rank to max_vocab_display to prevent out-of-range curves
+                    if rank > max_vocab_display:
+                        rank = max_vocab_display  # Put overflow at the max visible rank
                     trajectory.append(float(rank))  # Use float for smoother curves
                 else:
                     trajectory.append(np.nan)
@@ -830,7 +833,7 @@ def _add_dual_probability_legend_improved(
 
         # Create new smaller axis for colorbar with small gap from main plot
         # Position at bottom 1/3, narrow, with appropriate spacing
-        small_cbar_ax = fig.add_axes([0.90, 0.15, 0.008, 0.25])  # [left, bottom, width, height]
+        small_cbar_ax = fig.add_axes([0.88, 0.15, 0.008, 0.25])  # [left, bottom, width, height]
 
         # Create colorbar in the smaller axis
         cbar = ColorbarBase(