fix(sync): run watched sync when a scheduled --sync hits the running instance

The Windows daily-sync task launches `AeroFetch.exe --sync`, but the single-
instance lock routes that relaunch to the `second-instance` handler whenever
AeroFetch is already open. The handler only focused the window and looked for a
link -- it never checked `isSyncLaunch(argv)` -- so the sync never ran. The daily
auto-download of new watched-source uploads therefore did nothing for minimize-
to-tray / always-on users (and the relaunch stole window focus each day).

Add a `runWatchedSync` main->renderer push: on a `--sync` relaunch the handler
now nudges the renderer to run syncWatched() instead of focusing, so the daily
sync fires whether AeroFetch was closed or already running.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/index.ts

@@ -260,6 +260,15 @@ if (isPrimaryInstance) {
   // link it carried and hand it to the window we already have.
   app.on('second-instance', (_e, argv) => {
     if (!mainWindow) return
+    // A scheduled `--sync` relaunch (Task Scheduler) hit the already-running instance:
+    // run the watched-source sync in this window instead of no-opping. Without this the
+    // daily auto-download never fires while AeroFetch is open — e.g. minimize-to-tray
+    // users. Deliberately does NOT focus the window, so the daily sync stays unobtrusive
+    // (mirrors the fresh-launch `--sync` showInactive path in createWindow).
+    if (isSyncLaunch(argv)) {
+      mainWindow.webContents.send(IpcChannels.runWatchedSync)
+      return
+    }
     focusWindow(mainWindow)
     const incomingUrl = extractIncomingUrl(argv)
     if (incomingUrl) mainWindow.webContents.send(IpcChannels.externalUrl, incomingUrl)