docs: update .env.example with compression configuration variables

- Add `APP_COMPRESSION_ENABLED`, `APP_COMPRESSION_THRESHOLD_BYTES`, and `APP_COMPRESSION_LEVEL`
- Document new settings to support paste compression features

Author: Pdzly

.env.example

@@ -34,6 +34,11 @@ APP_BASE_FOLDER_PATH=./files
 APP_MIN_STORAGE_MB=1024
 APP_KEEP_DELETED_PASTES_TIME_HOURS=336
 
+# Compression settings
+APP_COMPRESSION_ENABLED=true
+APP_COMPRESSION_THRESHOLD_BYTES=512
+APP_COMPRESSION_LEVEL=6
+
 # Caching
 APP_CACHE_SIZE_LIMIT=1000
 APP_CACHE_TTL=300