Make TicketCard issue and PR chips clickable

[dhilgaertner]

Summary

• Extract LinkChip from SessionDetailView.swift into its own file so it can be reused beyond the session header.
• Replace the static purple ticketPRBadge and the plain #N issue-number text in TicketCard with gold LinkChips — every row now has a clickable Issue #N chip, and rows with a linked PR also show a PR #N chip. Both open the URL in the default browser, matching the session-header interaction.

Closes #171

Test plan

• make build succeeds
• Open the ticket board: every row shows an Issue #N chip; rows with a linked PR also show a PR #N chip
• Click Issue #N → opens the issue in the default browser
• Click PR #N → opens the PR in the default browser
• Rows without a linked PR show only the issue chip (no dead PR chip)
• Chip styling matches the session-header chips (gold capsule, same icons)
• Session detail view still renders Issue / PR / Repo chips correctly (regression check on the LinkChip move)

🤖 Generated with Claude Code

[dgershman]

Code & Security Review

Critical Issues

None found.

Security Review

Strengths:

• URL validation via URL(string:) before calling NSWorkspace.shared.open() — prevents crashes on malformed strings
• No user-controlled data flows into shell commands or unsafe APIs
• PR link only renders when both prNumber and prURL are non-nil (the if let prNum, let prURL guard), preventing dead chips with no destination

Concerns:

• None. NSWorkspace.shared.open() delegates URL handling to the OS, which is the standard safe pattern for macOS apps.

Code Quality

• Clean extraction: LinkChip moved from SessionDetailView.swift into its own file with zero functional change — the diff confirms the struct is byte-identical before and after the move
• Good guard tightening (TicketBoardView.swift:413): The old ticketPRBadge accepted an optional url: String? and silently rendered a non-clickable badge when nil. The new code requires both prNumber and prURL via if let, so no chip renders when there's no URL — strictly better behavior
• Consistent styling: Both issue and PR chips now use the same gold LinkChip style, replacing the old purple ticketPRBadge and plain #N text. This unifies the visual language between the session header and ticket board
• Net deletion: +45 / -54 — the refactor removes more code than it adds, which is a good sign for a reuse extraction
• LinkChip is internal (default access), which is correct — it's used within the CrowUI module only

Summary Table

Priority	Issue
Green	Consider adding accessibilityLabel to LinkChip for VoiceOver (e.g., "Open Issue #42 in browser")

Recommendation: Approve — straightforward extraction + reuse with no regressions, correct nil-guarding, and consistent UI.