fix: gate startup reconcile on renderer readiness

Defer the productive FolderMonitor startup scan until the renderer has registered its candidate listener and acknowledged readiness. Keep the handshake idempotent across duplicate signals, reloads, window closure, shutdown, paused startup, and renderer initialization failure without delaying unrelated startup work.

Preserve the real over-limit queue count while clamping finite progressbar ARIA values, and cover both regressions with hidden Electron and preload ordering tests.

tests/package-build-files.test.js

@@ -345,6 +345,54 @@ test('close readiness is signaled only after the renderer explicitly finishes in
   ]);
 });
 
+test('folder monitor readiness is emitted once and only after the candidate listener exists', () => {
+  const order = [];
+  const listeners = new Map();
+  let exposedApi = null;
+  const electronMock = {
+    contextBridge: {
+      exposeInMainWorld: (_name, api) => { exposedApi = api; }
+    },
+    ipcRenderer: {
+      invoke: () => Promise.resolve(),
+      on: (channel, listener) => {
+        listeners.set(channel, listener);
+        order.push(`listen:${channel}`);
+      },
+      send: channel => { order.push(`send:${channel}`); },
+      removeAllListeners: () => {}
+    },
+    webUtils: {
+      getPathForFile: () => ''
+    }
+  };
+  const originalLoad = Module._load;
+  const preloadPath = require.resolve('../preload');
+  delete require.cache[preloadPath];
+  Module._load = function (request, parent, isMain) {
+    if (request === 'electron') return electronMock;
+    return originalLoad.call(this, request, parent, isMain);
+  };
+  try {
+    require(preloadPath);
+  } finally {
+    Module._load = originalLoad;
+  }
+
+  exposedApi.signalFolderMonitorReady();
+  let received = null;
+  exposedApi.onFolderMonitorNewFiles(files => { received = files; });
+  exposedApi.signalFolderMonitorReady();
+  exposedApi.signalFolderMonitorReady();
+  listeners.get('folder-monitor:new-files')({}, [{ path: 'C:\\watch\\ready.mkv' }]);
+
+  assert.deepEqual(order, [
+    'listen:folder-monitor:new-files',
+    'send:folder-monitor:renderer-ready'
+  ]);
+  assert.deepEqual(received, [{ path: 'C:\\watch\\ready.mkv' }]);
+});
+
 test('preload exposes account cooldown snapshots and removes their listener during cleanup', async () => {
   const listeners = new Map();
   const invocations = [];
@@ -812,7 +860,7 @@ test('startup keeps a missing configured folder disconnected without disabling a
   assert.notEqual(startupEnd, -1);
   const startup = mainSource.slice(startupStart, startupEnd);
 
-  assert.match(startup, /fm\s*&&\s*fm\.enabled\s*&&\s*fm\.folderPath[\s\S]*?await startFolderMonitor\(fm\)/u);
+  assert.match(startup, /fm\s*&&\s*fm\.enabled\s*&&\s*fm\.folderPath[\s\S]*?await startFolderMonitor\(fm,\s*\{\s*deferStartupReconcile:\s*true\s*\}\)/u);
   assert.doesNotMatch(startup, /fm\.paused\s*!==\s*true/u);
   assert.doesNotMatch(startup, /folderMonitor\.scan\(\{\s*emitFiles:\s*true,\s*trigger:\s*'startup'\s*\}\)/u);
   assert.doesNotMatch(startup, /folderMonitor:\s*\{\s*\.\.\.fm,\s*enabled:\s*false\s*\}/u);