Show poster thumbnails in the detail panes

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

README.md

@@ -8,6 +8,10 @@ A terminal UI to search for movies and series with [Radarr](https://radarr.video
   optionally start the automatic search.
 - **Interactive search**: list the releases Radarr/Sonarr find (approved or rejected, with reasons),
   sort and filter them (by approval, quality, x265 / x264 / AV1, HDR, Dolby Vision, audio format, language), and grab one. Series: pick a season or a single episode first.
+- **Posters**: a small poster thumbnail in the detail panes, drawn with colored half-block
+  characters (needs a terminal with colors; works over SSH). Library items use the copy stored in
+  Radarr/Sonarr; search results are downloaded from the metadata provider's image host
+  (TMDb, TheTVDB). Turn it off with `"ui": {"covers": false}`.
 - **Library**: browse movies (top) and series (below) with a details pane on the right, filter by status (missing / downloaded / monitored) and by file properties (quality, x265 / x264 / AV1, HDR, Dolby Vision, audio format, language), toggle
   monitoring, trigger searches. Series open into seasons and episodes with per-season and
   per-episode monitoring, automatic search and release search.
@@ -38,7 +42,7 @@ Settings → General.
   "radarr":  { "url": "http://localhost:7878", "apikey": "...", "default_quality_profile": "HD-1080p", "default_root_folder": "/movies" },
   "sonarr":  { "url": "http://localhost:8989", "apikey": "...", "default_quality_profile": "HD-1080p", "default_root_folder": "/tv" },
   "sabnzbd": { "url": "http://localhost:8080", "apikey": "..." },
-  "ui":      { "refresh_seconds": 3 }
+  "ui":      { "refresh_seconds": 3, "covers": true }
 }
 ```