fix(get_config): SSH fallback when REST API returns empty (HP 2530/YA firmware)

HP 2530 switches with YA firmware do not expose /rest/v7/running-config.
_get_config_via_ssh() opens a temporary netmiko session to run
'show running-config' as fallback when the API endpoint returns 404.

napalm_procurve/procurve.py

@@ -565,7 +565,13 @@ class ProcurveDriver(ConfigLifecycleMixin, SwitchDriver):
     ) -> Dict[str, str]:
         """Return device configuration."""
         if self._transport == "api":
-            return self._api.get_config()
+            result = self._api.get_config()
+            if result.get("running"):
+                return result
+            # REST endpoint not available on this firmware (e.g. HP 2530 / YA series).
+            # Fall back to a temporary SSH connection to run show running-config.
+            running = self._get_config_via_ssh()
+            return {"running": running, "startup": "", "candidate": ""}
 
         running = ""
         startup = ""
@@ -580,6 +586,22 @@ class ProcurveDriver(ConfigLifecycleMixin, SwitchDriver):
 
         return {"running": running, "startup": startup, "candidate": candidate}
 
+    def _get_config_via_ssh(self) -> str:
+        """Open a one-shot SSH session to retrieve running-config.
+
+        Used as fallback when the REST API does not expose the config endpoint
+        (e.g. HP 2530 / YA firmware).  Returns empty string on any failure.
+        """
+        try:
+            conn = ConnectHandler(**self._netmiko_kwargs())
+            try:
+                return conn.send_command("show running-config")
+            finally:
+                conn.disconnect()
+        except Exception as exc:
+            logger.warning("SSH config fallback failed for %s: %s", self.hostname, exc)
+            return ""
+
     # ------------------------------------------------------------------
     # NAPALM: get_environment
     # ------------------------------------------------------------------