Implement media storage and processing features: update configuration in .env.example and appsettings files, enhance Docker setup for media storage, and add media-related services and database entities. Include ffmpeg for media handling and adjust Kestrel settings for large file uploads.

.gitignore

@@ -77,3 +77,6 @@ dist-ssr/
 .env
 .env.local
 .env.*.local
+
+# Локальное медиахранилище для dev-запуска (Storage__RootPath в appsettings.Development.json)
+.dev-media/