Graph labels only visible for salience > 0.5, most nodes unlabeled

[CalebisGross]

Problem

`internal/web/static/index.html` line ~1501: Label opacity is set to 0 for nodes with salience <= 0.5. Since default salience is 0.5, most nodes will have invisible labels.

Impact

The graph is mostly unlabeled circles with no way to identify what they represent without hovering.

Fix

Show labels for all nodes (perhaps truncated), or use a much lower threshold like 0.2.

[CalebisGross]

Fixed in #41 — lowered threshold from 0.5 to 0.2, dim low-salience labels instead of hiding.