Require mpv plugin in first-run setup

src/main/runtime/first-run-setup-service.test.ts

@@ -251,6 +251,48 @@ test('setup service reopens when external-yomitan completion later has no extern
   });
 });
 
+test('setup service reopens when a completed setup no longer has the mpv plugin installed', async () => {
+  await withTempDir(async (root) => {
+    const configDir = path.join(root, 'SubMiner');
+    fs.mkdirSync(configDir, { recursive: true });
+    fs.writeFileSync(path.join(configDir, 'config.jsonc'), '{}');
+
+    const completedService = createFirstRunSetupService({
+      configDir,
+      getYomitanDictionaryCount: async () => 2,
+      detectPluginInstalled: () => true,
+      installPlugin: async () => ({
+        ok: true,
+        pluginInstallStatus: 'installed',
+        pluginInstallPathSummary: '/tmp/mpv',
+        message: 'ok',
+      }),
+      onStateChanged: () => undefined,
+    });
+
+    await completedService.ensureSetupStateInitialized();
+    await completedService.markSetupCompleted();
+
+    const service = createFirstRunSetupService({
+      configDir,
+      getYomitanDictionaryCount: async () => 2,
+      detectPluginInstalled: () => false,
+      installPlugin: async () => ({
+        ok: true,
+        pluginInstallStatus: 'installed',
+        pluginInstallPathSummary: null,
+        message: 'ok',
+      }),
+      onStateChanged: () => undefined,
+    });
+
+    const snapshot = await service.ensureSetupStateInitialized();
+    assert.equal(snapshot.state.status, 'incomplete');
+    assert.equal(snapshot.canFinish, false);
+    assert.equal(snapshot.pluginStatus, 'required');
+  });
+});
+
 test('setup service keeps completed when external-yomitan completion later has internal dictionaries available', async () => {
   await withTempDir(async (root) => {
     const configDir = path.join(root, 'SubMiner');