[FEATURE] Redesign shelter setup window UI/UX

[kacime]

Description

Redesign the shelter setup window to improve user experience and match the new design specifications.

Requirements

• Display total disk size when a path is selected
• Update styling to match the new mockup design
• Replace storage size input with a slider ranging from 0-100% of total disk space
• Replace bandwidth limiter with a checkbox to enable/disable + input field for MB/s limit only

Acceptance Criteria

• Total disk size is displayed after path selection
• UI matches the provided mockup design
• Storage allocation uses a percentage slider (0-100% of total disk)
• Slider shows corresponding size in GB/TB based on percentage
• Bandwidth limiter has enable/disable checkbox
• When enabled, bandwidth input accepts only MB/s values
• All form validation works properly
• Settings are saved correctly with new format

Resources

• Design mockup: link to mockup