test: add behavioral assertions to composer tests

Upgrade 8 composer test files from shape-only typeof checks to behavioral
assertions that invoke returned handlers and verify injected dependencies are
actually called, following the mpv-runtime-composer pattern.

src/main/runtime/composers/anilist-setup-composer.test.ts

@@ -3,11 +3,14 @@ import assert from 'node:assert/strict';
 import { composeAnilistSetupHandlers } from './anilist-setup-composer';
 
 test('composeAnilistSetupHandlers returns callable setup handlers', () => {
+  const calls: string[] = [];
   const composed = composeAnilistSetupHandlers({
     notifyDeps: {
       hasMpvClient: () => false,
       showMpvOsd: () => {},
-      showDesktopNotification: () => {},
+      showDesktopNotification: (title, opts) => {
+        calls.push(`notify:${opts.body}`);
+      },
       logInfo: () => {},
     },
     consumeTokenDeps: {
@@ -37,4 +40,16 @@ test('composeAnilistSetupHandlers returns callable setup handlers', () => {
   assert.equal(typeof composed.consumeAnilistSetupTokenFromUrl, 'function');
   assert.equal(typeof composed.handleAnilistSetupProtocolUrl, 'function');
   assert.equal(typeof composed.registerSubminerProtocolClient, 'function');
+
+  // notifyAnilistSetup forwards to showDesktopNotification when no MPV client
+  composed.notifyAnilistSetup('Setup complete');
+  assert.deepEqual(calls, ['notify:Setup complete']);
+
+  // handleAnilistSetupProtocolUrl returns false for non-subminer URLs
+  const handled = composed.handleAnilistSetupProtocolUrl('https://other.example.com/');
+  assert.equal(handled, false);
+
+  // handleAnilistSetupProtocolUrl returns true for subminer:// URLs
+  const handledProtocol = composed.handleAnilistSetupProtocolUrl('subminer://anilist-setup?code=abc');
+  assert.equal(handledProtocol, true);
 });