Slider component doesn't expose createSlider methods

[johnleider]

Problem

The Slider component doesn't expose createSlider methods (setValue, snap, percent, fromPercent, stepUp, stepDown, etc.) to consumers. These methods appear on the composable API page but not on the component API page.

Root Cause

1. SliderRoot.vue never calls defineExpose — template refs can't access slider methods
2. The API generator (generate-api.ts) uses vue-component-meta which only extracts props/events/slots, not exposed methods

Proposed Fix

• Add defineExpose to SliderRoot with slider methods
• Consider also passing methods through slot props (matching TabsRoot pattern)
• Update API generator to surface defineExpose members on component docs pages