Add SSH host identity rotation controls

src/ssh_transport.h

@@ -124,6 +124,14 @@ esp_err_t ssh_transport_init(void);
 esp_err_t ssh_transport_start(void);
 esp_err_t ssh_transport_stop(void);
 
+/* Conditional off-HTTPD rotation: both generations checked/reserved before stop.
+ * Zero generations retain canonical rotate/reset semantics. A failed stop skips
+ * mutation/start; persistence failure may already have disconnected all SSH.
+ * committed reports irreversible publication even if restart subsequently fails. */
+esp_err_t ssh_transport_replace_identity(uint32_t service_generation,
+                                         uint32_t identity_generation,
+                                         bool reset, bool *committed);
+
 /* Serialize stop, persistent host-key replacement, and conditional restart. */
 esp_err_t ssh_transport_replace_host_key(bool reset);