fix: support delete in --no-db mode (GH#822)

Add CreateTombstone() to MemoryStorage and deleteBatchFallback() to
handle deletion when SQLite is not available. This fixes the error
"tombstone operation not supported by this storage backend" when
using bd delete with --no-db flag.

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

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

cmd/bd/delete.go

@@ -437,8 +437,9 @@ func deleteBatch(_ *cobra.Command, issueIDs []string, force bool, dryRun bool, c
 	// Type assert to SQLite storage
 	d, ok := store.(*sqlite.SQLiteStorage)
 	if !ok {
-		fmt.Fprintf(os.Stderr, "Error: batch delete not supported by this storage backend\n")
-		os.Exit(1)
+		// Fallback for non-SQLite storage (e.g., MemoryStorage in --no-db mode)
+		deleteBatchFallback(issueIDs, force, dryRun, cascade, jsonOutput, hardDelete, reason)
+		return
 	}
 	// Verify all issues exist
 	issues := make(map[string]*types.Issue)
@@ -566,6 +567,114 @@ func deleteBatch(_ *cobra.Command, issueIDs []string, force bool, dryRun bool, c
 		}
 	}
 }
+
+// deleteBatchFallback handles batch deletion for non-SQLite storage (e.g., MemoryStorage in --no-db mode)
+// It iterates through issues one by one, creating tombstones for each.
+func deleteBatchFallback(issueIDs []string, force bool, dryRun bool, cascade bool, jsonOutput bool, hardDelete bool, reason string) {
+	ctx := rootCtx
+
+	// Cascade not supported in fallback mode
+	if cascade {
+		fmt.Fprintf(os.Stderr, "Error: --cascade not supported in --no-db mode\n")
+		os.Exit(1)
+	}
+
+	// Verify all issues exist first
+	issues := make(map[string]*types.Issue)
+	notFound := []string{}
+	for _, id := range issueIDs {
+		issue, err := store.GetIssue(ctx, id)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error getting issue %s: %v\n", id, err)
+			os.Exit(1)
+		}
+		if issue == nil {
+			notFound = append(notFound, id)
+		} else {
+			issues[id] = issue
+		}
+	}
+	if len(notFound) > 0 {
+		fmt.Fprintf(os.Stderr, "Error: issues not found: %s\n", strings.Join(notFound, ", "))
+		os.Exit(1)
+	}
+
+	// Preview mode
+	if dryRun || !force {
+		fmt.Printf("\n%s\n", ui.RenderFail("⚠️  DELETE PREVIEW"))
+		fmt.Printf("\nIssues to delete (%d):\n", len(issueIDs))
+		for _, id := range issueIDs {
+			if issue := issues[id]; issue != nil {
+				fmt.Printf("  %s: %s\n", id, issue.Title)
+			}
+		}
+		if dryRun {
+			fmt.Printf("\n(Dry-run mode - no changes made)\n")
+		} else {
+			fmt.Printf("\n%s\n", ui.RenderWarn("This operation cannot be undone!"))
+			fmt.Printf("To proceed, run: %s\n",
+				ui.RenderWarn("bd delete "+strings.Join(issueIDs, " ")+" --force"))
+		}
+		return
+	}
+
+	// Delete each issue
+	deleteActor := getActorWithGit()
+	deletedCount := 0
+	depsRemoved := 0
+
+	for _, issueID := range issueIDs {
+		// Remove dependencies (outgoing)
+		depRecords, err := store.GetDependencyRecords(ctx, issueID)
+		if err == nil {
+			for _, dep := range depRecords {
+				if err := store.RemoveDependency(ctx, dep.IssueID, dep.DependsOnID, deleteActor); err == nil {
+					depsRemoved++
+				}
+			}
+		}
+
+		// Remove dependencies (inbound)
+		dependents, err := store.GetDependents(ctx, issueID)
+		if err == nil {
+			for _, dep := range dependents {
+				if err := store.RemoveDependency(ctx, dep.ID, issueID, deleteActor); err == nil {
+					depsRemoved++
+				}
+			}
+		}
+
+		// Create tombstone
+		if err := createTombstone(ctx, issueID, deleteActor, reason); err != nil {
+			fmt.Fprintf(os.Stderr, "Error creating tombstone for %s: %v\n", issueID, err)
+			continue
+		}
+		deletedCount++
+	}
+
+	// Hard delete: remove from JSONL immediately
+	if hardDelete {
+		for _, id := range issueIDs {
+			_ = removeIssueFromJSONL(id)
+		}
+	}
+
+	// Schedule auto-flush
+	markDirtyAndScheduleFlush()
+
+	// Output results
+	if jsonOutput {
+		outputJSON(map[string]interface{}{
+			"deleted":              issueIDs,
+			"deleted_count":        deletedCount,
+			"dependencies_removed": depsRemoved,
+		})
+	} else {
+		fmt.Printf("%s Deleted %d issue(s)\n", ui.RenderPass("✓"), deletedCount)
+		fmt.Printf("  Removed %d dependency link(s)\n", depsRemoved)
+	}
+}
+
 // showDeletionPreview shows what would be deleted
 func showDeletionPreview(issueIDs []string, issues map[string]*types.Issue, cascade bool, depError error) {
 	fmt.Printf("\n%s\n", ui.RenderFail("⚠️  DELETE PREVIEW"))