NeXroll 2.0.0-beta.12

Windows testers: This fixes a long-standing bug — the YouTube PO-token plugin was never actually bundled into the Windows build, so the provider looked installed but trailer downloads couldn't use it. After updating, the provider reports healthy and downloads work. Plus a batch of thumbnail and Community Prerolls fixes.

Fixed

• YouTube PO-token downloads work in the packaged Windows app. The yt-dlp bgutil plugin shipped only as an empty namespace, so the token provider ran but yt-dlp couldn't talk to it — and the System page reported "Components installed; provider not healthy yet" even while it was running. The plugin is now bundled, and the install/status check is accurate.
• Preroll thumbnails display reliably and stay put. Three fixes: (1) thumbnails for files whose name contains ... returned "Invalid path" and never loaded; (2) a leftover cache-first service worker served stale/blank thumbnails that a hard refresh couldn't clear — preroll media is now served fresh from the network; (3) after rebuilding thumbnails, regenerated images now load instead of the cached old one.
• "Reinitialize Thumbnails" shows its status on the Library page (where the button is), with processed / generated / cleaned counts.
• Community auto-match "Link" works — the community ID (a URL path with slashes and encoded characters) now travels in the request body instead of the URL.
• Index-build progress shows on the Community page regardless of where the rebuild was started; clicking Refresh during a build attaches to it instead of erroring "already in progress".

Added

• Edit Preroll modal shows the file's full path (under "Current file").
• Download Diagnostics button on the Logs page (Settings → Logs), alongside JSON/CSV export.

Upgrade-safe. Full details in CHANGELOG.md.