feat(project-editor): add draft/publish status, dirty tracking, save/publish to facade

Wires ProjectValidator into ProjectEditorFacade and extends ProjectEditorState
with status ('draft'|'published') and lastSavedBootstrap. Adds dirty computed
(diffed against lastSavedBootstrap), validationIssues computed, and save()/publish()
methods. publish() calls PlatformRuntimeService.reloadFromBootstrap() and refuses
when validation issues exist. loadBootstrap() seeds lastSavedBootstrap so a
freshly-loaded bootstrap is not dirty.

src/app/features/project-editor/models/project-editor.model.ts

@@ -18,6 +18,8 @@ export interface ProjectEditorState {
   bootstrap: BootstrapConfig | null;
   importError: string | null;
   activeSection: ProjectEditorSectionId;
+  status: 'draft' | 'published';
+  lastSavedBootstrap: BootstrapConfig | null;
 }
 
 export interface ProjectEditorWidgetPreset {