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/network/download.py

@@ -37,10 +37,16 @@ def run_download(post, headers: Optional[dict] = None):
 
     if ismagnet:
         link = result
+        if not link:
+            consoleLog("Failed to retrieve magnet link")
+            return
         add_magnet(link)
         add_download_log(post.get("title", "Unknown"), "", link, False)
     else:
         link, link_headers = result if isinstance(result, tuple) else (result, None)
+        if not link:
+            consoleLog("Failed to retrieve download link")
+            return
         final_headers = headers or link_headers
         add_direct_download(link, post.get("title", "Unknown"), headers=final_headers, single_threaded=final_headers is not None)