Replaces stat card layout with functional dashboard: - Prominent spool count with "Add Spool" button - Paginated list of all spools sorted by last used - Low stock alert badge (< 100g threshold) - Color swatch, name, material, and remaining weight columns - Clickable rows navigate to spool detail - Secondary stats for filaments and vendors Closes #12 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>