Implements comprehensive issue management via AT Protocol: - createIssue(): Create new issues with title and optional body - listIssues(): List and filter issues by repository - getIssue(): Retrieve specific issue details - updateIssue(): Update issue title and/or body with atomic CID swap - closeIssue(): Mark issue as closed via state record - deleteIssue(): Permanently delete an issue Features: - Uses generated lexicon types (IssueRecord) for type safety - Uses requireAuth() helper for authentication validation - Uses parseIssueUri() internal helper to eliminate duplication - Clear error messages with context - Repository filtering in list operations - Ownership verification for update/delete Includes comprehensive test coverage (23 tests passing) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>