Emdash source with visual editor image upload fix

Fixes:
1. media.ts: wrap placeholder generation in try-catch
2. toolbar.ts: check r.ok, display error message in popover

templates/starter/emdash-env.d.ts

@@ -0,0 +1,37 @@
+// Generated by EmDash on dev server start
+// Do not edit manually
+
+/// <reference types="emdash/locals" />
+
+import type { PortableTextBlock } from "emdash";
+
+export interface Page {
+  id: string;
+  slug: string | null;
+  status: string;
+  title: string;
+  content?: PortableTextBlock[];
+  createdAt: Date;
+  updatedAt: Date;
+  publishedAt: Date | null;
+}
+
+export interface Post {
+  id: string;
+  slug: string | null;
+  status: string;
+  title: string;
+  featured_image?: { id: string; src?: string; alt?: string; width?: number; height?: number };
+  content?: PortableTextBlock[];
+  excerpt?: string;
+  createdAt: Date;
+  updatedAt: Date;
+  publishedAt: Date | null;
+}
+
+declare module "emdash" {
+  interface EmDashCollections {
+    pages: Page;
+    posts: Post;
+  }
+}