feat(mail): accept multiple message IDs in delete command

Allow `gt mail delete` to accept multiple message IDs at once,
matching the existing behavior of archive, mark-read, and mark-unread.

Also adds --body as an alias for --message in mail reply.

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

internal/cmd/mail.go

@@ -176,12 +176,16 @@ Exits silently with code 1 if no unread messages.`,
 }
 
 var mailDeleteCmd = &cobra.Command{
-	Use:   "delete <message-id>",
+	Use:   "delete <message-id> [message-id...]",
-	Short: "Delete a message",
+	Short: "Delete messages",
-	Long: `Delete (acknowledge) a message.
+	Long: `Delete (acknowledge) one or more messages.
 
-This closes the message in beads.`,
+This closes the messages in beads.
-	Args: cobra.ExactArgs(1),
+
+Examples:
+  gt mail delete hq-abc123
+  gt mail delete hq-abc123 hq-def456 hq-ghi789`,
+	Args: cobra.MinimumNArgs(1),
 	RunE: runMailDelete,
 }
 
@@ -461,6 +465,7 @@ func init() {
 	// Reply flags
 	mailReplyCmd.Flags().StringVarP(&mailReplySubject, "subject", "s", "", "Override reply subject (default: Re: <original>)")
 	mailReplyCmd.Flags().StringVarP(&mailReplyMessage, "message", "m", "", "Reply message body")
+	mailReplyCmd.Flags().StringVar(&mailReplyMessage, "body", "", "Reply message body (alias for --message)")
 
 	// Search flags
 	mailSearchCmd.Flags().StringVar(&mailSearchFrom, "from", "", "Filter by sender address")

internal/cmd/mail_inbox.go

@@ -224,11 +224,6 @@ func runMailPeek(cmd *cobra.Command, args []string) error {
 }
 
 func runMailDelete(cmd *cobra.Command, args []string) error {
-	if len(args) == 0 {
-		return errors.New("msgID argument required")
-	}
-	msgID := args[0]
-
 	// Determine which inbox
 	address := detectSender()
 
@@ -237,11 +232,32 @@ func runMailDelete(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	// Delete all specified messages
+	deleted := 0
+	var errors []string
+	for _, msgID := range args {
 		if err := mailbox.Delete(msgID); err != nil {
-		return fmt.Errorf("deleting message: %w", err)
+			errors = append(errors, fmt.Sprintf("%s: %v", msgID, err))
+		} else {
+			deleted++
+		}
 	}
 
+	// Report results
+	if len(errors) > 0 {
+		fmt.Printf("%s Deleted %d/%d messages\n",
+			style.Bold.Render("⚠"), deleted, len(args))
+		for _, e := range errors {
+			fmt.Printf("  Error: %s\n", e)
+		}
+		return fmt.Errorf("failed to delete %d messages", len(errors))
+	}
+
+	if len(args) == 1 {
 		fmt.Printf("%s Message deleted\n", style.Bold.Render("✓"))
+	} else {
+		fmt.Printf("%s Deleted %d messages\n", style.Bold.Render("✓"), deleted)
+	}
 	return nil
 }
 

internal/cmd/mail_thread.go

@@ -80,6 +80,9 @@ func runMailThread(cmd *cobra.Command, args []string) error {
 }
 
 func runMailReply(cmd *cobra.Command, args []string) error {
+	if mailReplyMessage == "" {
+		return fmt.Errorf("required flag \"message\" or \"body\" not set")
+	}
 	msgID := args[0]
 
 	// Get message body from positional arg or flag (positional takes precedence)