Deduplicate UI patterns: empty states, badges, headers

[dhilgaertner]

Problem

Several UI patterns are repeated across views without a shared component:

• Empty states — TicketBoardView, ReviewBoardView, GlobalTerminalView all have ContentUnavailableView with icon + title + subtitle + action button, each slightly different
• Badge capsules — .padding(.horizontal, 6).background(...).clipShape(Capsule()) appears in 5+ views
• Section headers with loading spinner — TicketBoardView, ReviewBoardView, AllowListView all have title + loading indicator + count

Proposed Improvement

Extract shared components:

• EmptyStateView(icon:title:subtitle:action:)
• BadgeCapsule(text:color:) modifier or view
• SectionHeader(title:isLoading:count:) — partially addressed by SectionHelpBanner but not fully

Effort

Low (1 hour). Small view extractions.

Files Affected

• Packages/CrowUI/Sources/CrowUI/TicketBoardView.swift
• Packages/CrowUI/Sources/CrowUI/ReviewBoardView.swift
• Packages/CrowUI/Sources/CrowUI/GlobalTerminalView.swift
• Packages/CrowUI/Sources/CrowUI/SessionListView.swift
• New: shared UI components

Priority: 10/10