refactor(main): split main.ts into focused runtime modules (#123)

src/main/runtime/windows-mpv-plugin-detection.test.ts

@@ -0,0 +1,18 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { detectWindowsMpvPluginRemovalCandidates } from './first-run-setup-plugin';
+
+test('Windows plugin removal candidates include portable directory installs', () => {
+  const mpvPath = 'C:\\tools\\mpv\\mpv.exe';
+  const portablePluginDir = 'C:\\tools\\mpv\\portable_config\\scripts\\subminer';
+  const existing = new Set([portablePluginDir]);
+
+  const candidates = detectWindowsMpvPluginRemovalCandidates({
+    homeDir: 'C:\\Users\\tester',
+    appDataDir: 'C:\\Users\\tester\\AppData\\Roaming',
+    mpvExecutablePath: mpvPath,
+    existsSync: (candidate) => existing.has(candidate),
+  });
+
+  assert.deepEqual(candidates, [{ path: portablePluginDir, kind: 'directory' }]);
+});