feat(log): auto-persist fallback path into settings

When the configured log path isn't writable and we fall back to
Desktop/userData, the working fallback now gets saved into
globalSettings.logFilePath automatically. Benefits:

  - Next session writes directly to the known-working path, no
    fallback ladder, no recurring toast warning.
  - The Settings input reflects the actual path in use, so users
    don't stay confused about where their uploads are being logged.
  - Live update via IPC — if the Settings view is currently open,
    the input value updates without needing a view switch.

Daily-log mode is handled: we strip the -YYYY-MM-DD suffix before
persisting so tomorrow's auto-rotation doesn't double-date the
filename.

main.js

@@ -290,6 +290,10 @@ function _flushUploadLog() {
       debugLog(`uploadLog append failed: ${err.message}`);
     } else if (target.isFallback && !_uploadLogFallbackWarned) {
       _uploadLogFallbackWarned = true;
+      // Auto-persist the working fallback into the user's config so the
+      // next session writes here directly (no more fallback ladder) and
+      // the Settings input reflects reality.
+      _persistFallbackLogPath(target.path);
       if (mainWindow && !mainWindow.isDestroyed()) {
         mainWindow.webContents.send('upload-log-fallback', { fallbackPath: target.path });
       }
@@ -298,6 +302,34 @@ function _flushUploadLog() {
   });
 }
 
+function _persistFallbackLogPath(workingPath) {
+  try {
+    const cfg = configStore.load();
+    const gs = cfg.globalSettings || {};
+    // If daily-log is on, workingPath has a date suffix (fileuploader-YYYY-MM-DD.log).
+    // Strip that before saving so the base path rolls forward to tomorrow's
+    // file correctly — otherwise the next day's getLogFilePath would append
+    // another date onto the already-dated base.
+    let toSave = workingPath;
+    if (gs.sessionLog) {
+      const dir = path.dirname(workingPath);
+      const base = path.basename(workingPath);
+      const stripped = base.replace(/-\d{4}-\d{2}-\d{2}(\.[^.]+)$/, '$1');
+      toSave = path.join(dir, stripped);
+    }
+    if (gs.logFilePath === toSave) return;
+    gs.logFilePath = toSave;
+    cfg.globalSettings = gs;
+    configStore.save({ globalSettings: gs }).catch(() => {});
+    _invalidateUploadLogTargetCache();
+    if (mainWindow && !mainWindow.isDestroyed()) {
+      mainWindow.webContents.send('log-path-auto-updated', { logFilePath: toSave });
+    }
+  } catch (err) {
+    debugLog(`persist fallback logpath failed: ${err.message}`);
+  }
+}
+
 function appendUploadLog(hoster, link, fileName) {
   const now = new Date();
   const pad = (n) => String(n).padStart(2, '0');

preload.js

@@ -108,6 +108,9 @@ contextBridge.exposeInMainWorld('api', {
     ipcRenderer.on('account-rotation-log', (_event, data) => callback(data));
   },
   openLogFolder: () => ipcRenderer.invoke('open-log-folder'),
+  onLogPathAutoUpdated: (callback) => {
+    ipcRenderer.on('log-path-auto-updated', (_event, data) => callback(data));
+  },
   // Remote Control
   remoteGetSettings: () => ipcRenderer.invoke('remote:get-settings'),
   remoteSaveSettings: (settings) => ipcRenderer.invoke('remote:save-settings', settings),

renderer/app.js

@@ -118,12 +118,19 @@ async function init() {
   });
   window.api.onShutdownCountdown(handleShutdownCountdown);
   window.api.onUploadLogFallback((data) => {
-    // Non-blocking toast instead of alert() — alert() in Electron halts the
-    // entire renderer main thread (including the upload table) until the user
-    // clicks OK. During a big batch that freezes everything.
     const path = data && data.fallbackPath ? data.fallbackPath : '(Fallback)';
     showCopyToast(`Log-Pfad nicht beschreibbar — schreibe nach: ${path}`, 8000);
   });
+  window.api.onLogPathAutoUpdated((data) => {
+    if (!data || !data.logFilePath) return;
+    // Keep the in-memory config and the visible Settings input in sync so
+    // the user sees the path that's actually being written to, and the
+    // next save from the UI doesn't revert it.
+    if (config && config.globalSettings) config.globalSettings.logFilePath = data.logFilePath;
+    const input = document.getElementById('logFilePathInput');
+    if (input) input.value = data.logFilePath;
+    showCopyToast(`Log-Pfad automatisch auf funktionierenden Ordner gesetzt`, 5000);
+  });
   window.api.onAccountRotationLog((entry) => {
     // Surface only the user-visible rotation events as toasts; full detail
     // goes to account-rotation.log. Keep it quiet otherwise.