initial working implementation of ssh agent

src-tauri/migrations/20240617142724_credential_split.sql

@@ -75,5 +75,6 @@ CREATE TABLE ssh_credentials (
     comment TEXT NOT NULL,
     public_key BLOB NOT NULL,
     private_key_enc BLOB NOT NULL,
-    nonce BLOB NOT NULL
+    nonce BLOB NOT NULL,
+    FOREIGN KEY(id) REFERENCES credentials(id) ON DELETE CASCADE
 );