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/auth-atproto/tests/resolve-handle.test.ts

@@ -0,0 +1,27 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+
+import { verifyHandleDID } from "../src/resolve-handle.js";
+
+describe("verifyHandleDID", () => {
+	const originalFetch = globalThis.fetch;
+
+	afterEach(() => {
+		globalThis.fetch = originalFetch;
+		vi.restoreAllMocks();
+	});
+
+	it("returns null for handles without a dot", async () => {
+		expect(await verifyHandleDID("localhost")).toBeNull();
+		expect(await verifyHandleDID("")).toBeNull();
+	});
+
+	it("returns null when resolution fails", async () => {
+		globalThis.fetch = vi.fn().mockRejectedValue(new Error("network error"));
+		expect(await verifyHandleDID("nobody.example.com")).toBeNull();
+	});
+
+	it("returns null when HTTP returns non-ok", async () => {
+		globalThis.fetch = vi.fn().mockResolvedValue(new Response("", { status: 404 }));
+		expect(await verifyHandleDID("nobody.example.com")).toBeNull();
+	});
+});