D3 force simulation parameters poorly tuned — nodes scatter #7

Problem

`internal/web/static/index.html` lines ~1473-1477: Hardcoded force simulation parameters:

• Charge strength: -300 (very strong repulsion)
• Link distance: 80 (fixed regardless of graph size)
• Center force: 0.05 (too weak to keep graph centered)
• Collision radius: `(salience * 30) + 4` (arbitrary)

Impact

Nodes fly apart, cluster at edges, or overlap depending on dataset size. No meaningful spatial organization.

Fix

Make parameters adaptive based on node count, or expose them as configurable sliders.