Outlier score badge on YouTube thumbnails

Scores every card against the median views of its own channel's last N
videos, badging the thumbnail above the duration stamp. Shorts and regular
videos are scored in separate pools, live streams in none. Baselines come
from YouTube's InnerTube endpoint, one request per channel, cached a day.
Interface in English and Turkish.

_locales/en/messages.json

@@ -0,0 +1,10 @@
+{
+  "extName": {
+    "message": "Outlier Badge",
+    "description": "Extension name"
+  },
+  "extDescription": {
+    "message": "Puts an outlier score on the corner of every YouTube thumbnail: the video's views over its own channel's median.",
+    "description": "Extension description"
+  }
+}