Improve failover controls and preserve manual switching state

.tmp-tests/harbor-startup-recovery-KP1brk/state.json

@@ -0,0 +1 @@
+{"schemaVersion":6,"revision":4,"profiles":[{"id":"profile-a","label":"Основной","subscriptionUrl":"https://provider.example/subscription-a","subscriptionConfig":null,"servers":[{"id":"server-a","label":"Server A","host":"a.example","port":443,"protocol":"vless"}],"userInfo":{},"fetchedAt":null,"desiredServerId":"server-a","lastRefreshAttemptAt":null,"lastRefreshErrorCode":null}],"desiredProfileId":"profile-a","appliedProfileId":"profile-a","appliedServerId":"server-a","appliedServerSnapshot":{"id":"server-a","label":"Server A","host":"a.example","port":443,"protocol":"vless"},"routeRules":[],"appliedRouteRules":[],"routeRulesRevision":0,"connectionDesired":"running"}