Document transcoded asset usage for Telegram media

Note that the service uses transcoded/optimized versions of assets
when available, not the original files.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

manifest.json

@@ -1,3 +1,3 @@
 {
-  "version": "1.28.0"
+  "version": "1.28.1"
 }