fix: Add locks, logging refactor, and bugfixes

Improve thread-safety, logging, and various bug fixes across the app.

Key changes:
- Add and use state.downloads_lock around accesses to state.active_downloads in multiple modules (UI, libtorrent, misc, direct downloads) to prevent race conditions.
- Prevent concurrent dl_status_loop runs using a non-blocking _loop_lock and ensure proper iteration over a snapshot of downloads.
- Add metadata timeout when waiting for torrent metadata and fix free-space check logic to remove or reject downloads appropriately.
- Refactor download log persistence: add _load_downloads and _save_downloads helpers and centralize JSON read/write logic in utils/logging/logs.py.
- Optimize DirectDownloadStatus speed window by switching to deque and using popleft to trim older samples.
- Trim console log widget to 500 lines to avoid unbounded growth.
- Add small state fields for custom image positioning (x/y and enabled flag).
- Fix Steamrip scraper caching behavior and make Uztracker return an empty list on fetch failures.
- Add defensive checks in run_download to handle missing links.

These changes focus on stability and correctness for concurrent download handling and durable logging.

src/utils/data/state.py

@@ -38,6 +38,9 @@ class AppState(QObject):
         self._image_opacity: int = 100
         self._image_as_wallpaper: bool = False
         self._image_position: str = "bottom-right"  # top-left, top-right, bottom-left, bottom-right, center
+        self._image_custom_position: bool = False
+        self._image_x: int = 0
+        self._image_y: int = 0
 
         # Trackers / Scraping
         self.posts: list[Dict[str,str]] | None = None  # titles, urls, author, seeders, leechers