chore: code health review - test fix and error comments (bd-9g1z, bd-ork0)

- Remove TestFindJSONLPathDefault from .test-skip (now passes)
- Add explanatory comments to 24 ignored error locations in cmd/bd:
  - Cobra flag methods (MarkHidden, MarkRequired, MarkDeprecated)
  - Best-effort cleanup/close operations
  - Process signaling operations

Part of code health review epic bd-tggf.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/bd/migrate_issues.go

@@ -708,6 +708,6 @@ func init() {
 	migrateIssuesCmd.Flags().Bool("strict", false, "Fail on orphaned dependencies or missing repos")
 	migrateIssuesCmd.Flags().Bool("yes", false, "Skip confirmation prompt")
 
-	_ = migrateIssuesCmd.MarkFlagRequired("from")
-	_ = migrateIssuesCmd.MarkFlagRequired("to")
+	_ = migrateIssuesCmd.MarkFlagRequired("from") // Only fails if flag missing (caught in tests)
+	_ = migrateIssuesCmd.MarkFlagRequired("to")   // Only fails if flag missing (caught in tests)
 }