feat(12.1-02): password and form-only fields, rules per operation and preset

- pact.FormVirtualFields lists form fields that are not model columns: never
  bound, filled or projected; their values reach the Form hooks through
  cabana.VirtualFieldsFromContext when the field's context allows the operation
- type: password is a masked field that must be listed as virtual
- pact.FormRules supplies the rule set per operation and replaces the model's
  Rules() for admin saves; a rule on a virtual field sees the submitted value
- preset on a text field follows another text field on the create form
- SPA: PasswordField, preset handling in FormView, empty password left out of
  an update
- README, docs, OpenAPI document, TS types and dist updated

modules/cabana/settings.go

@@ -63,9 +63,12 @@ func compileSetting(pluginID string, item pact.SettingsItem, fsys fs.FS) (*Compi
 	}
 	for _, field := range fields {
 		// A settings screen has no admin controller to own actions or view models.
-		if field.Type == "widget" || field.Type == "partial" || field.Type == "fileupload" {
+		if field.Type == "widget" || field.Type == "partial" || field.Type == "fileupload" || field.Type == "password" {
 			return nil, fmt.Errorf("cabana: setting %s field %s: type %s is not supported on a settings form", item.Code, field.Name, field.Type)
 		}
+		if field.Preset != nil {
+			return nil, fmt.Errorf("cabana: setting %s field %s: preset is not supported on a settings form", item.Code, field.Name)
+		}
 	}
 	form := &FormSchema{Name: item.Label, ModelClass: item.Model, Fields: fields}
 	columns := modelColumns(model)