Add GitLab issue URL support

[tupe12334]

• Update resolveParams() in src/app/open/page.tsx to detect GitLab issues (e.g., gitlab_issue param alongside owner, repo)
• Update IssueParams type in src/app/open/issue-card.tsx to include "gitlab" variant
• Update buildWorktreeUrl() to construct worktree://open?owner=X&repo=Y&issue=N for GitLab (same params as GitHub, or add gitlab=true flag if needed)
• Accept links from the future gitlab-comment-action integration

[github-actions]

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