Align progressive disclosure feature boxes precisely at Module 05 boundary

Fixed visual alignment issue where dormant and active feature boxes were
floating separately instead of meeting at the activation point.

Key improvements:
1. Feature boxes now use anchor=east (dormant) and anchor=west (active)
2. Both positioned at exactly x=6 (Module 05 vertical line)
3. Dormant boxes END at the red line, active boxes START at the red line
4. Made gray dotted module boundary lines darker (gray!60 instead of gray!40)
5. Increased box width to 2.0cm for better visual balance

Visual logic now perfectly clear:
- Gray boxes extend left from M05 = features exist but dormant
- Orange boxes extend right from M05 = features now active
- Red vertical line at M05 = exact moment of activation
- Boxes meet precisely at the boundary with no gap or overlap

This addresses user feedback: 'why aren't the .backward() and so forth really
aligned exactly at that point?' Now they ARE precisely aligned, making the
discrete activation event visually obvious.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

paper/paper.tex

@@ -675,16 +675,16 @@ print(x.grad)  # [6.0] - dy/dx = 2x
 \begin{tikzpicture}[
     scale=0.9,
     every node/.style={font=\scriptsize},
-    dormant/.style={rectangle, draw=gray!60, fill=gray!20, text=gray!70, minimum width=1.6cm, minimum height=0.5cm},
-    active/.style={rectangle, draw=orange!80, fill=orange!30, text=black, font=\scriptsize\bfseries, minimum width=1.6cm, minimum height=0.5cm}
+    dormant/.style={rectangle, draw=gray!70, fill=gray!20, text=gray!70, minimum width=2.0cm, minimum height=0.5cm, anchor=east},
+    active/.style={rectangle, draw=orange!80, fill=orange!30, text=black, font=\scriptsize\bfseries, minimum width=2.0cm, minimum height=0.5cm, anchor=west}
 ]
 
 % Timeline axis
 \draw[thick, ->] (0,0) -- (14,0) node[right, font=\scriptsize] {Modules};
 
-% Module boundaries as vertical lines
+% Module boundaries as vertical lines (darker)
 \foreach \x/\label in {1/01, 3.5/03, 6/05, 8.5/09, 11/13, 13.5/20} {
-    \draw[gray!40, dotted] (\x, 0) -- (\x, 5.5);
+    \draw[gray!60, dotted] (\x, 0) -- (\x, 5.5);
     \node[below, font=\tiny] at (\x, -0.3) {\texttt{M\label}};
 }
 
@@ -692,25 +692,24 @@ print(x.grad)  # [6.0] - dy/dx = 2x
 \draw[red!60, very thick] (6, 0) -- (6, 5.5);
 \node[above, font=\scriptsize\bfseries, red!70] at (6, 5.7) {ACTIVATE};
 
-% Feature layers - stacked with vertical alignment at Module 05
-% Layer 1: Core features (always active)
-\node[active] at (1.5, 1.0) {\texttt{.data}};
-\node[active] at (3.5, 1.0) {\texttt{.shape}};
+% Feature layers - dormant boxes end AT M05, active boxes start AT M05
+% Layer 1: Core features (always active - span both sides)
+\node[active, minimum width=4.0cm, anchor=center] at (3.5, 1.0) {\texttt{.data}, \texttt{.shape}};
 \node[left, font=\tiny] at (0.2, 1.0) {Core};
 
-% Layer 2: Gradient features - transition at Module 05
+% Layer 2: Gradient features - boxes meet exactly at x=6 (Module 05 line)
 % .requires_grad
-\node[dormant] at (2.25, 2.2) {\texttt{.requires\_grad}};
-\node[active] at (8.5, 2.2) {\texttt{.requires\_grad}};
+\node[dormant] at (6, 2.2) {\texttt{.requires\_grad}};
+\node[active] at (6, 2.2) {\texttt{.requires\_grad}};
 \node[left, font=\tiny] at (0.2, 2.2) {Gradient};
 
 % .grad
-\node[dormant] at (2.75, 3.1) {\texttt{.grad}};
-\node[active] at (8.5, 3.1) {\texttt{.grad}};
+\node[dormant] at (6, 3.1) {\texttt{.grad}};
+\node[active] at (6, 3.1) {\texttt{.grad}};
 
 % .backward()
-\node[dormant] at (2.0, 4.0) {\texttt{.backward()}};
-\node[active] at (8.5, 4.0) {\texttt{.backward()}};
+\node[dormant] at (6, 4.0) {\texttt{.backward()}};
+\node[active] at (6, 4.0) {\texttt{.backward()}};
 
 % Annotations - positioned at top
 \node[align=center, font=\tiny, text width=4.5cm] at (3, 6.5) {
@@ -726,8 +725,8 @@ print(x.grad)  # [6.0] - dy/dx = 2x
 };
 
 % Legend
-\node[dormant, minimum width=1.0cm, minimum height=0.4cm] at (2.5, -1.2) {Dormant};
-\node[active, minimum width=1.0cm, minimum height=0.4cm] at (5.5, -1.2) {Active};
+\node[dormant, minimum width=1.0cm, minimum height=0.4cm, anchor=center] at (2.5, -1.2) {Dormant};
+\node[active, minimum width=1.0cm, minimum height=0.4cm, anchor=center] at (5.5, -1.2) {Active};
 
 \end{tikzpicture}
 \caption{Progressive disclosure manages cognitive load through runtime feature activation. From Module 01, students see the complete Tensor API including gradient methods (\texttt{.backward()}, \texttt{.grad}, \texttt{.requires\_grad}), but these features remain dormant (gray, dashed)—they exist as placeholders that return gracefully. In Module 05, runtime method enhancement activates full autograd functionality (orange, solid) without breaking earlier code. This creates three learning benefits: (1) students learn the complete API early, avoiding interface surprise later; (2) Module 01 code continues working unchanged when autograd activates, demonstrating forward compatibility; (3) visible but inactive features create curiosity-driven questions ("Why does \texttt{.backward()} exist if we can't use it yet?") that motivate curriculum progression.}