feat(list): Add type aliases for --type flag (gt-pvhsv)

Add convenience aliases for common type names:
- mr → merge-request
- feat → feature
- mol → molecule

Applied to bd list, bd ready, and bd export commands.
Case-insensitive matching (MR, Mr, mr all work).

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

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

cmd/bd/export.go

@@ -140,6 +140,7 @@ Examples:
 		// Additional filter flags
 		assignee, _ := cmd.Flags().GetString("assignee")
 		issueType, _ := cmd.Flags().GetString("type")
+		issueType = util.NormalizeIssueType(issueType) // Expand aliases (mr→merge-request, etc.)
 		labels, _ := cmd.Flags().GetStringSlice("label")
 		labelsAny, _ := cmd.Flags().GetStringSlice("label-any")
 		priorityMinStr, _ := cmd.Flags().GetString("priority-min")
@@ -582,7 +583,7 @@ func init() {
 	// Filter flags
 	registerPriorityFlag(exportCmd, "")
 	exportCmd.Flags().StringP("assignee", "a", "", "Filter by assignee")
-	exportCmd.Flags().StringP("type", "t", "", "Filter by type (bug, feature, task, epic, chore, merge-request, molecule, gate)")
+	exportCmd.Flags().StringP("type", "t", "", "Filter by type (bug, feature, task, epic, chore, merge-request, molecule, gate). Aliases: mr→merge-request, feat→feature, mol→molecule")
 	exportCmd.Flags().StringSliceP("label", "l", []string{}, "Filter by labels (AND: must have ALL)")
 	exportCmd.Flags().StringSlice("label-any", []string{}, "Filter by labels (OR: must have AT LEAST ONE)")