feat: Add --assignee flag to template instantiate, fix mail inbox --identity

- Add --assignee flag to `bd template instantiate` for work delegation
  - Assigns the root epic to specified agent/user
  - Child issues retain their template-defined assignees
  - Enables Gas Town orchestration: instantiate + assign in one step

- Add missing --identity flag to `bd mail inbox` for consistency
  - All mail subcommands now support --identity override

- Delete obsolete HANDOFF-template-redesign.md (work complete)

- Add test for assignee override behavior

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

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

cmd/bd/mail.go

@@ -130,6 +130,7 @@ func init() {
 	// Inbox command flags
 	mailInboxCmd.Flags().StringVar(&mailFrom, "from", "", "Filter by sender")
 	mailInboxCmd.Flags().IntVar(&mailPriorityFlag, "priority", -1, "Filter by priority (0-4)")
+	mailInboxCmd.Flags().StringVar(&mailIdentity, "identity", "", "Override recipient identity")
 
 	// Read command flags
 	mailReadCmd.Flags().StringVar(&mailIdentity, "identity", "", "Override identity for access check")

cmd/bd/template.go

@@ -383,6 +383,7 @@ Example:
 		ctx := rootCtx
 		dryRun, _ := cmd.Flags().GetBool("dry-run")
 		varFlags, _ := cmd.Flags().GetStringSlice("var")
+		assignee, _ := cmd.Flags().GetString("assignee")
 
 		// Parse variables
 		vars := make(map[string]string)
@@ -446,7 +447,11 @@ Example:
 			fmt.Printf("\nDry run: would create %d issues from template %s\n\n", len(subgraph.Issues), templateID)
 			for _, issue := range subgraph.Issues {
 				newTitle := substituteVariables(issue.Title, vars)
-				fmt.Printf("  - %s (from %s)\n", newTitle, issue.ID)
+				suffix := ""
+				if issue.ID == subgraph.Root.ID && assignee != "" {
+					suffix = fmt.Sprintf(" (assignee: %s)", assignee)
+				}
+				fmt.Printf("  - %s (from %s)%s\n", newTitle, issue.ID, suffix)
 			}
 			if len(vars) > 0 {
 				fmt.Printf("\nVariables:\n")
@@ -458,7 +463,7 @@ Example:
 		}
 
 		// Clone the subgraph
-		result, err := cloneSubgraph(ctx, store, subgraph, vars, actor)
+		result, err := cloneSubgraph(ctx, store, subgraph, vars, assignee, actor)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error instantiating template: %v\n", err)
 			os.Exit(1)
@@ -484,6 +489,7 @@ func init() {
 
 	templateInstantiateCmd.Flags().StringSlice("var", []string{}, "Variable substitution (key=value)")
 	templateInstantiateCmd.Flags().Bool("dry-run", false, "Preview what would be created")
+	templateInstantiateCmd.Flags().String("assignee", "", "Assign the root epic to this agent/user")
 
 	templateCmd.AddCommand(templateListCmd)
 	templateCmd.AddCommand(templateShowCmd)
@@ -734,7 +740,8 @@ func substituteVariables(text string, vars map[string]string) string {
 }
 
 // cloneSubgraph creates new issues from the template with variable substitution
-func cloneSubgraph(ctx context.Context, s storage.Storage, subgraph *TemplateSubgraph, vars map[string]string, actorName string) (*InstantiateResult, error) {
+// If assignee is non-empty, it will be set on the root epic
+func cloneSubgraph(ctx context.Context, s storage.Storage, subgraph *TemplateSubgraph, vars map[string]string, assignee string, actorName string) (*InstantiateResult, error) {
 	if s == nil {
 		return nil, fmt.Errorf("no database connection")
 	}
@@ -746,6 +753,12 @@ func cloneSubgraph(ctx context.Context, s storage.Storage, subgraph *TemplateSub
 	err := s.RunInTransaction(ctx, func(tx storage.Transaction) error {
 		// First pass: create all issues with new IDs
 		for _, oldIssue := range subgraph.Issues {
+			// Determine assignee: use override for root epic, otherwise keep template's
+			issueAssignee := oldIssue.Assignee
+			if oldIssue.ID == subgraph.Root.ID && assignee != "" {
+				issueAssignee = assignee
+			}
+
 			newIssue := &types.Issue{
 				// Don't set ID - let the system generate it
 				Title:              substituteVariables(oldIssue.Title, vars),
@@ -756,7 +769,7 @@ func cloneSubgraph(ctx context.Context, s storage.Storage, subgraph *TemplateSub
 				Status:             types.StatusOpen, // Always start fresh
 				Priority:           oldIssue.Priority,
 				IssueType:          oldIssue.IssueType,
-				Assignee:           oldIssue.Assignee,
+				Assignee:           issueAssignee,
 				EstimatedMinutes:   oldIssue.EstimatedMinutes,
 				CreatedAt:          time.Now(),
 				UpdatedAt:          time.Now(),

cmd/bd/template_test.go

@@ -450,7 +450,7 @@ func TestCloneSubgraph(t *testing.T) {
 		}
 
 		vars := map[string]string{"version": "2.0.0"}
-		result, err := cloneSubgraph(ctx, s, subgraph, vars, "test-user")
+		result, err := cloneSubgraph(ctx, s, subgraph, vars, "", "test-user")
 		if err != nil {
 			t.Fatalf("cloneSubgraph failed: %v", err)
 		}
@@ -490,7 +490,7 @@ func TestCloneSubgraph(t *testing.T) {
 		}
 
 		vars := map[string]string{"service": "api-gateway"}
-		result, err := cloneSubgraph(ctx, s, subgraph, vars, "test-user")
+		result, err := cloneSubgraph(ctx, s, subgraph, vars, "", "test-user")
 		if err != nil {
 			t.Fatalf("cloneSubgraph failed: %v", err)
 		}
@@ -549,7 +549,7 @@ func TestCloneSubgraph(t *testing.T) {
 			t.Fatalf("loadTemplateSubgraph failed: %v", err)
 		}
 
-		result, err := cloneSubgraph(ctx, s, subgraph, nil, "test-user")
+		result, err := cloneSubgraph(ctx, s, subgraph, nil, "", "test-user")
 		if err != nil {
 			t.Fatalf("cloneSubgraph failed: %v", err)
 		}
@@ -562,6 +562,52 @@ func TestCloneSubgraph(t *testing.T) {
 			t.Errorf("Status = %s, want %s", newEpic.Status, types.StatusOpen)
 		}
 	})
+
+	t.Run("assignee override applies to root epic only", func(t *testing.T) {
+		epic := h.createIssue("Root Epic", "", types.TypeEpic, 1)
+		child := h.createIssue("Child Task", "", types.TypeTask, 2)
+		h.addParentChild(child.ID, epic.ID)
+
+		// Set assignees on template
+		err := s.UpdateIssue(ctx, epic.ID, map[string]interface{}{"assignee": "template-owner"}, "test-user")
+		if err != nil {
+			t.Fatalf("Failed to set epic assignee: %v", err)
+		}
+		err = s.UpdateIssue(ctx, child.ID, map[string]interface{}{"assignee": "child-owner"}, "test-user")
+		if err != nil {
+			t.Fatalf("Failed to set child assignee: %v", err)
+		}
+
+		subgraph, err := loadTemplateSubgraph(ctx, s, epic.ID)
+		if err != nil {
+			t.Fatalf("loadTemplateSubgraph failed: %v", err)
+		}
+
+		// Clone with assignee override
+		result, err := cloneSubgraph(ctx, s, subgraph, nil, "new-assignee", "test-user")
+		if err != nil {
+			t.Fatalf("cloneSubgraph failed: %v", err)
+		}
+
+		// Root epic should have override assignee
+		newEpic, err := s.GetIssue(ctx, result.NewEpicID)
+		if err != nil {
+			t.Fatalf("Failed to get cloned epic: %v", err)
+		}
+		if newEpic.Assignee != "new-assignee" {
+			t.Errorf("Epic assignee = %q, want %q", newEpic.Assignee, "new-assignee")
+		}
+
+		// Child should keep template assignee
+		newChildID := result.IDMapping[child.ID]
+		newChild, err := s.GetIssue(ctx, newChildID)
+		if err != nil {
+			t.Fatalf("Failed to get cloned child: %v", err)
+		}
+		if newChild.Assignee != "child-owner" {
+			t.Errorf("Child assignee = %q, want %q", newChild.Assignee, "child-owner")
+		}
+	})
 }
 
 // TestExtractAllVariables tests extracting variables from entire subgraph