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/admin/tests/lib/utils.test.ts

@@ -0,0 +1,64 @@
+import { describe, it, expect } from "vitest";
+
+import { cn, slugify } from "../../src/lib/utils";
+
+describe("slugify", () => {
+	it("converts basic text to slug", () => {
+		expect(slugify("Hello World")).toBe("hello-world");
+	});
+
+	it("handles unicode and diacritics", () => {
+		expect(slugify("café résumé")).toBe("cafe-resume");
+	});
+
+	it("strips special characters", () => {
+		expect(slugify("hello! @world# $")).toBe("hello-world");
+	});
+
+	it("collapses multiple hyphens", () => {
+		expect(slugify("hello---world")).toBe("hello-world");
+	});
+
+	it("trims leading/trailing hyphens", () => {
+		expect(slugify("-hello-world-")).toBe("hello-world");
+	});
+
+	it("handles underscores as separators", () => {
+		expect(slugify("hello_world")).toBe("hello-world");
+	});
+
+	it("returns empty string for empty input", () => {
+		expect(slugify("")).toBe("");
+	});
+
+	it("handles all special characters", () => {
+		expect(slugify("!@#$%")).toBe("");
+	});
+
+	it("handles mixed case", () => {
+		expect(slugify("HeLLo WoRLD")).toBe("hello-world");
+	});
+
+	it("handles multiple spaces", () => {
+		expect(slugify("hello   world")).toBe("hello-world");
+	});
+});
+
+describe("cn", () => {
+	it("merges class names", () => {
+		expect(cn("foo", "bar")).toBe("foo bar");
+	});
+
+	it("handles conditional classes", () => {
+		const condition = false;
+		expect(cn("foo", condition && "bar", "baz")).toBe("foo baz");
+	});
+
+	it("merges conflicting tailwind classes", () => {
+		expect(cn("p-4", "p-2")).toBe("p-2");
+	});
+
+	it("handles undefined and null", () => {
+		expect(cn("foo", undefined, null, "bar")).toBe("foo bar");
+	});
+});