refactor: Remove YAML template system entirely

Removes the legacy YAML-based simple template system that provided
bug/epic/feature templates for --from-template flag on bd create.

Removed:
- cmd/bd/templates/bug.yaml, epic.yaml, feature.yaml
- Template struct and all YAML loading functions in template.go
- --from-template flag from bd create command
- template_security_test.go (tested removed functions)
- YAML template tests from template_test.go

The Beads template system remains (epics with "template" label,
instantiated via bd template instantiate with variable substitution).

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

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

cmd/bd/template_test.go

@@ -10,188 +10,6 @@ import (
 	"github.com/steveyegge/beads/internal/types"
 )
 
-func TestLoadBuiltinTemplate(t *testing.T) {
-	tests := []struct {
-		name          string
-		templateName  string
-		wantType      string
-		wantPriority  int
-		wantHasLabels bool
-	}{
-		{
-			name:          "epic template",
-			templateName:  "epic",
-			wantType:      "epic",
-			wantPriority:  1,
-			wantHasLabels: true,
-		},
-		{
-			name:          "bug template",
-			templateName:  "bug",
-			wantType:      "bug",
-			wantPriority:  1,
-			wantHasLabels: true,
-		},
-		{
-			name:          "feature template",
-			templateName:  "feature",
-			wantType:      "feature",
-			wantPriority:  2,
-			wantHasLabels: true,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			tmpl, err := loadBuiltinTemplate(tt.templateName)
-			if err != nil {
-				t.Fatalf("loadBuiltinTemplate() error = %v", err)
-			}
-
-			if tmpl.Type != tt.wantType {
-				t.Errorf("Type = %v, want %v", tmpl.Type, tt.wantType)
-			}
-
-			if tmpl.Priority != tt.wantPriority {
-				t.Errorf("Priority = %v, want %v", tmpl.Priority, tt.wantPriority)
-			}
-
-			if tt.wantHasLabels && len(tmpl.Labels) == 0 {
-				t.Errorf("Expected labels but got none")
-			}
-
-			if tmpl.Description == "" {
-				t.Errorf("Expected description but got empty string")
-			}
-
-			if tmpl.AcceptanceCriteria == "" {
-				t.Errorf("Expected acceptance criteria but got empty string")
-			}
-		})
-	}
-}
-
-func TestLoadBuiltinTemplateNotFound(t *testing.T) {
-	_, err := loadBuiltinTemplate("nonexistent")
-	if err == nil {
-		t.Errorf("Expected error for nonexistent template, got nil")
-	}
-}
-
-func TestLoadCustomTemplate(t *testing.T) {
-	// Create temporary directory for test
-	tmpDir := t.TempDir()
-	t.Chdir(tmpDir)
-
-	// Create .beads/templates directory
-	templatesDir := filepath.Join(".beads", "templates")
-	if err := os.MkdirAll(templatesDir, 0755); err != nil {
-		t.Fatalf("Failed to create templates directory: %v", err)
-	}
-
-	// Create a custom template
-	customTemplate := `name: custom-test
-description: Test custom template
-type: chore
-priority: 3
-labels:
-  - test
-  - custom
-design: Test design
-acceptance_criteria: Test acceptance
-`
-	templatePath := filepath.Join(templatesDir, "custom-test.yaml")
-	if err := os.WriteFile(templatePath, []byte(customTemplate), 0644); err != nil {
-		t.Fatalf("Failed to write template: %v", err)
-	}
-
-	// Load the custom template
-	tmpl, err := loadCustomTemplate("custom-test")
-	if err != nil {
-		t.Fatalf("loadCustomTemplate() error = %v", err)
-	}
-
-	if tmpl.Name != "custom-test" {
-		t.Errorf("Name = %v, want custom-test", tmpl.Name)
-	}
-
-	if tmpl.Type != "chore" {
-		t.Errorf("Type = %v, want chore", tmpl.Type)
-	}
-
-	if tmpl.Priority != 3 {
-		t.Errorf("Priority = %v, want 3", tmpl.Priority)
-	}
-
-	if len(tmpl.Labels) != 2 {
-		t.Errorf("Expected 2 labels, got %d", len(tmpl.Labels))
-	}
-}
-
-func TestLoadTemplate_PreferCustomOverBuiltin(t *testing.T) {
-	// Create temporary directory for test
-	tmpDir := t.TempDir()
-	t.Chdir(tmpDir)
-
-	// Create .beads/templates directory
-	templatesDir := filepath.Join(".beads", "templates")
-	if err := os.MkdirAll(templatesDir, 0755); err != nil {
-		t.Fatalf("Failed to create templates directory: %v", err)
-	}
-
-	// Create a custom template with same name as builtin
-	customTemplate := `name: epic
-description: Custom epic override
-type: epic
-priority: 0
-labels:
-  - custom-epic
-design: Custom design
-acceptance_criteria: Custom acceptance
-`
-	templatePath := filepath.Join(templatesDir, "epic.yaml")
-	if err := os.WriteFile(templatePath, []byte(customTemplate), 0644); err != nil {
-		t.Fatalf("Failed to write template: %v", err)
-	}
-
-	// loadTemplate should prefer custom over builtin
-	tmpl, err := loadTemplate("epic")
-	if err != nil {
-		t.Fatalf("loadTemplate() error = %v", err)
-	}
-
-	// Should get custom template (priority 0) not builtin (priority 1)
-	if tmpl.Priority != 0 {
-		t.Errorf("Priority = %v, want 0 (custom template)", tmpl.Priority)
-	}
-
-	if len(tmpl.Labels) != 1 || tmpl.Labels[0] != "custom-epic" {
-		t.Errorf("Expected custom-epic label, got %v", tmpl.Labels)
-	}
-}
-
-func TestIsBuiltinTemplate(t *testing.T) {
-	tests := []struct {
-		name     string
-		template string
-		want     bool
-	}{
-		{"epic is builtin", "epic", true},
-		{"bug is builtin", "bug", true},
-		{"feature is builtin", "feature", true},
-		{"custom is not builtin", "custom", false},
-		{"random is not builtin", "random", false},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if got := isBuiltinTemplate(tt.template); got != tt.want {
-				t.Errorf("isBuiltinTemplate(%v) = %v, want %v", tt.template, got, tt.want)
-			}
-		})
-	}
-}
-
 // =============================================================================
 // Beads Template Tests (for bd template instantiate)
 // =============================================================================