RDL v0.1.1 Preview — thumbnail improvements

Improved screenshot discovery and fixed empty preview counts.

• Background scanning now uses cached image-search previews when original image hosts fail, rather than doing so only for the selected map.
• Review counts include only downloaded, decoded, screened images. Broken links no longer create empty preview lists.
• Wiki/forum/ModDB searches take priority, with labeled YouTube thumbnail choices as a fallback. Video thumbnails require a user choice.
• Stronger diagram filters check Wiki image categories and flat blueprint-style image content. Search results distinguish a map pack from an identically named level in another pack.
• Map readme and confirmed Wiki titles guide searches. The matcher checks up to three early map articles if a pack article lacks screenshots.
• Existing chosen images are preserved. Updating clears earlier failed-search cooldowns once; reopen RDL and run Scan.

Validation: 98 regression checks pass. A bounded live sample found cached, decoded previews for seven of eight map files, including a verified Wiki image for Arrival; many other results were video choices. This is not a coverage estimate for the full collection. Map-click assignment, compact layout and applying a real cached image through the picker passed. All 21 existing local artwork choices were preserved.

Known limits: search coverage varies, some names need a full map title, and source sites can block downloads. Filters cannot guarantee that every result is a good representative screenshot; review choices before applying them. No games, engines, maps, mods, source code or developer tools are included.