feat(deployment): add deployment history and rollback support

.env.docker

@@ -35,7 +35,10 @@ PORT=4000
 JWT_SECRET=dev-super-secret-jwt-key-change-in-production-32chars
 JWT_EXPIRES_IN=7d
 
-# Encryption key for SSH private keys (AES-256)
+# Required in production. Generate once, store securely, and keep it stable:
+# openssl rand -hex 32
+# Changing this value without re-encrypting stored secrets makes existing
+# credentials and deployment rollback snapshots unreadable.
 ENCRYPTION_KEY=dev-32-char-encryption-key-here!
 
 # /* -------------------------- Public URL / callbacks ------------------------ */