Add documentation

Author: alexdachin

apps/server/src/assets/config-sample.ini

@@ -67,3 +67,18 @@ oauthIssuerName=
 # Set the issuer icon for OAuth/OpenID authentication
 # This is the icon of the service that will be used to verify the user's identity
 oauthIssuerIcon=
+
+[ExternalBlobStorage]
+# External blob storage allows large attachments to be stored as separate files
+# instead of being embedded in the SQLite database. This can improve database
+# performance and simplify backup strategies for large files.
+#
+# When enabled=false (default), all attachments are stored in the database
+# When enabled=true, attachments larger than thresholdBytes are stored as files
+# in the external-blobs directory within your data directory
+enabled=false
+
+# Threshold size in bytes - attachments larger than this will be stored externally
+# Default is 100KB (102400 bytes), which balances performance and flexibility
+# See https://www.sqlite.org/intern-v-extern-blob.html for performance considerations
+thresholdBytes=102400