feat: add hard delete flag and opal clean command

Add --hard flag to `opal delete` for permanent removal and a new
`opal clean` command to bulk-purge soft-deleted tasks with optional
--older duration filter.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

opal-task/cmd/delete.go

@@ -8,19 +8,25 @@ import (
 	"github.com/spf13/cobra"
 )
 
+var hardDeleteFlag bool
+
 var deleteCmd = &cobra.Command{
 	Use:   "delete [filter...]",
 	Short: "Delete tasks",
 	Run: func(cmd *cobra.Command, args []string) {
 		parsed := getParsedArgs(cmd)
-		if err := deleteTasks(parsed.Filters); err != nil {
+		if err := deleteTasks(parsed.Filters, hardDeleteFlag); err != nil {
 			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
 			os.Exit(1)
 		}
 	},
 }
 
-func deleteTasks(args []string) error {
+func init() {
+	deleteCmd.Flags().BoolVar(&hardDeleteFlag, "hard", false, "Permanently remove task from database")
+}
+
+func deleteTasks(args []string, hard bool) error {
 	filter, err := engine.ParseFilter(args)
 	if err != nil {
 		return err
@@ -53,15 +59,24 @@ func deleteTasks(args []string) error {
 		return fmt.Errorf("no tasks matched filter")
 	}
 
+	action := "delete"
+	if hard {
+		action = "permanently delete"
+	}
+
 	if dryRunFlag {
-		fmt.Print(engine.FormatTaskConfirmList("delete", tasks, ws))
+		fmt.Print(engine.FormatTaskConfirmList(action, tasks, ws))
 		fmt.Println("Dry run — no changes made.")
 		return nil
 	}
 
-	if len(tasks) > 1 {
-		fmt.Print(engine.FormatTaskConfirmList("delete", tasks, ws))
-		fmt.Printf("Proceed? (y/N): ")
+	if len(tasks) > 1 || hard {
+		fmt.Print(engine.FormatTaskConfirmList(action, tasks, ws))
+		if hard {
+			fmt.Printf("This cannot be undone. Proceed? (y/N): ")
+		} else {
+			fmt.Printf("Proceed? (y/N): ")
+		}
 		var confirm string
 		fmt.Scanln(&confirm)
 		if confirm != "y" && confirm != "Y" {
@@ -71,14 +86,20 @@ func deleteTasks(args []string) error {
 	}
 
 	for _, task := range tasks {
-		task.Delete(false) // Soft delete
-		engine.RecordUndo("delete", task.UUID)
+		task.Delete(hard)
+		if !hard {
+			engine.RecordUndo("delete", task.UUID)
+		}
 	}
 
+	verb := "Deleted"
+	if hard {
+		verb = "Permanently deleted"
+	}
 	if len(tasks) == 1 {
-		fmt.Printf("Deleted task %s\n", engine.FormatTaskSummary(tasks[0], ws))
+		fmt.Printf("%s task %s\n", verb, engine.FormatTaskSummary(tasks[0], ws))
 	} else {
-		fmt.Printf("Deleted %d task(s).\n", len(tasks))
+		fmt.Printf("%s %d task(s).\n", verb, len(tasks))
 	}
 	return nil
 }