Document the intent and nuances of recent fixes:
internal/importer/utils.go:
- RenameImportedIssuePrefixes: explain the three ID formats (sequential,
hash-based, hierarchical) and how prefix renaming preserves identity
- isValidIDSuffix: document why dots are allowed (hierarchical parent-child
relationships) and what characters are rejected
cmd/bd/deletion_tracking.go:
- isIssueNotFoundError: explain why "not found" is success during merge
(issue may be tombstoned, never existed locally, or manually deleted)
- Deletion loop: document what "accepted deletions" means and why we
tolerate missing issues during the pruning phase