feat(14.3-01): add summer new with a starter route and relative go.work

- build.NewApp writes sm-<name>-app: go.mod with a relative framework
  replace, go.work, summer.yaml, config/ and a starter plugin
- make:plugin gains an opt-in starter route (GET /{$}) in the same
  routes.go template; plain make:plugin output is unchanged
- plugin:add writes go.work use paths relative to the go.work directory
- bonfire accepts new as a bare tool command name

cmd/summer/main.go

@@ -34,6 +34,7 @@ func toolCommands() []bonfire.Command {
 		makeJobCommand(),
 		makeAdminControllerCommand(),
 		addPluginCommand(),
+		newCommand(),
 		devCommand(),
 		parityProxyCommand(),
 		parityRecordCommand(),
@@ -297,3 +298,35 @@ func addPluginCommand() bonfire.Command {
 		},
 	}
 }
+
+func newCommand() bonfire.Command {
+	return bonfire.Command{
+		Name:        "new",
+		Description: "Create a SummerCMS application in sm-<name>-app",
+		Args: []bonfire.Arg{{
+			Name:        "name",
+			Description: "Application name: lower-case letters and digits, starting with a letter; not a Go keyword, main or internal",
+			Required:    true,
+		}},
+		Flags: []bonfire.Flag{
+			{Name: "framework", Description: "Path to the framework checkout"},
+		},
+		Run: func(ctx context.Context, in bonfire.Input, out bonfire.Output) error {
+			name, ok := in.Argument("name")
+			if !ok || name == "" {
+				return fmt.Errorf("new requires an application name")
+			}
+			dir, err := os.Getwd()
+			if err != nil {
+				return err
+			}
+			framework, _ := in.Flag("framework")
+			_, err = build.NewApp(ctx, build.NewOptions{
+				Name:      name,
+				Parent:    dir,
+				Framework: framework,
+			}, out)
+			return err
+		},
+	}
+}