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

packages/core/tests/unit/visual-editing/editable.test.ts

@@ -0,0 +1,67 @@
+import { describe, expect, it } from "vitest";
+
+import { createEditable, createNoop } from "../../../src/visual-editing/editable.js";
+
+describe("createEditable", () => {
+	it("returns entry-level annotation when spread", () => {
+		const edit = createEditable("posts", "my-post");
+		expect({ ...edit }).toEqual({
+			"data-emdash-ref": '{"collection":"posts","id":"my-post"}',
+		});
+	});
+
+	it("includes status and hasDraft in entry-level annotation", () => {
+		const edit = createEditable("posts", "my-post", {
+			status: "published",
+			hasDraft: true,
+		});
+		expect({ ...edit }).toEqual({
+			"data-emdash-ref":
+				'{"collection":"posts","id":"my-post","status":"published","hasDraft":true}',
+		});
+	});
+
+	it("includes status/hasDraft in field-level annotations", () => {
+		const edit = createEditable("posts", "my-post", {
+			status: "published",
+			hasDraft: true,
+		});
+		expect(edit.title).toEqual({
+			"data-emdash-ref":
+				'{"collection":"posts","id":"my-post","status":"published","hasDraft":true,"field":"title"}',
+		});
+	});
+
+	it("returns field-level annotation for property access", () => {
+		const edit = createEditable("posts", "my-post");
+		expect(edit.title).toEqual({
+			"data-emdash-ref": '{"collection":"posts","id":"my-post","field":"title"}',
+		});
+	});
+
+	it("handles nested fields via bracket notation", () => {
+		const edit = createEditable("posts", "my-post");
+		expect(edit["hero.src"]).toEqual({
+			"data-emdash-ref": '{"collection":"posts","id":"my-post","field":"hero.src"}',
+		});
+	});
+
+	it("serializes to JSON correctly", () => {
+		const edit = createEditable("posts", "my-post");
+		expect(JSON.stringify({ edit })).toBe(
+			'{"edit":{"data-emdash-ref":"{\\"collection\\":\\"posts\\",\\"id\\":\\"my-post\\"}"}}',
+		);
+	});
+});
+
+describe("createNoop", () => {
+	it("returns empty object", () => {
+		const edit = createNoop();
+		expect({ ...edit }).toEqual({});
+	});
+
+	it("property access returns undefined", () => {
+		const edit = createNoop();
+		expect((edit as Record<string, unknown>).title).toBeUndefined();
+	});
+});