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.

preload.js

@@ -1,5 +1,8 @@
 const { contextBridge, ipcRenderer, webUtils } = require('electron');
 
+let folderMonitorCandidateListenerReady = false;
+let folderMonitorReadySent = false;
+
 contextBridge.exposeInMainWorld('api', {
   // Config
   getConfig: () => ipcRenderer.invoke('get-config'),
@@ -97,6 +100,13 @@ contextBridge.exposeInMainWorld('api', {
   automationResume: () => ipcRenderer.invoke('automation:resume'),
   onFolderMonitorNewFiles: (callback) => {
     ipcRenderer.on('folder-monitor:new-files', (_event, data) => callback(data));
+    folderMonitorCandidateListenerReady = true;
+  },
+  signalFolderMonitorReady: () => {
+    if (!folderMonitorCandidateListenerReady || folderMonitorReadySent) return false;
+    folderMonitorReadySent = true;
+    ipcRenderer.send('folder-monitor:renderer-ready');
+    return true;
   },
   onAutomationStatus: (callback) => {
     ipcRenderer.on('automation:status', (_event, data) => callback(data));
@@ -176,6 +186,8 @@ contextBridge.exposeInMainWorld('api', {
   // File path from drag & drop (Electron 33+ compatible)
   getPathForFile: (file) => webUtils.getPathForFile(file),
   removeAllListeners: () => {
+    folderMonitorCandidateListenerReady = false;
+    folderMonitorReadySent = false;
     ipcRenderer.removeAllListeners('upload-progress');
     ipcRenderer.removeAllListeners('upload-batch-done');
     ipcRenderer.removeAllListeners('upload-stats');