Frontend: Implement grouped roles & permissions view in Admin Console

Description

Build the full frontend experience for the user-grouped roles and permissions view, per the approved Figma design — collapsed summary, expanded detail, interaction logic, API integration, and existing search/filter support.

Checklist:

• Build collapsed view component (per-user summary row: name, role count, badges, etc.)
• Build expanded view component (nested role/permission detail per user)
• Implement expand/collapse logic per user, plus "expand all"/"collapse all" (if included in the design)
• Persist expansion state during the session (if applicable)
• Connect to the new possible endpoint(s)
• Handle loading, error, and empty states (no users/roles)
• Adapt existing search (by user) and filters (by role/course) to the grouped structure
• Validate implementation against Figma design (colors, spacing, typography)
• Unit tests for components (collapsed/expanded, expand-collapse logic)

Figma Design