[Phase 2.2] Build feedback listing page with filters and sorting

[Andreas-Froyland]

Goal

Main feedback list view. Card-based layout with filtering and sorting. The primary surface users interact with.

Depends on: #10 (creation form) - users need to create feedback before they can list it

Layout

• Sidebar: category filter pills + status filter
• Main area: feedback cards in a scrollable list
• Top bar: sort selector (Newest / Most Upvoted) + "New Feedback" button

Each feedback card shows:

• Title (clickable → detail view)
• Category badge (colored)
• Vote count placeholder (upvoting in [Phase 2.4] Implement upvoting system #12)
• Status badge (Open / In Progress / Done / Closed)
• Author avatar (GitHub avatar or generic anon icon)
• Relative timestamp ("2 hours ago")

Filters

• Category — filter by one or more categories
• Status — filter by status (default: show Open + In Progress)
• Filters persist in URL query params (shareable links)

Sorting

• Newest — most recent first (default)
• Most Upvoted — highest vote count first (implement after [Phase 2.4] Implement upvoting system #12)

Pagination

• Infinite scroll or "Load more" button
• Cursor-based (not offset) for performance

Empty state

• Friendly message + illustration when no feedback exists yet
• CTA button to create the first item