perf(node): throttle RPC polling during sync so block download isn't slowed

The full-node wallet polled the daemon at the per-tab cadence regardless of sync state.
On the Peers/Network tab that meant getpeerinfo every 5s + core every 5s + a full
transaction scan on every new block — and blocks arrive fast during sync. Each of those
calls takes the daemon's cs_main lock, the same lock block connection needs, so the node
synced noticeably slower than on the lightweight Console tab (core 10s, no peer polling).

Make the refresh cadence sync-aware:
- RefreshScheduler::kSyncProfile {core 10s, transactions/addresses/peers disabled} is applied
  to ALL tabs while state_.sync.syncing, and reverts to the per-tab profile when sync ends.
  applyRefreshPolicy() picks the profile; update() re-applies it on the syncing<->synced
  transition. This suppresses getpeerinfo and the per-block tx scan during sync (that data is
  incomplete mid-sync anyway) — every tab now syncs as fast as Console.
- collectCoreRefreshResult(rpc, includeBalance): skip z_gettotalbalance (wallet lock + cs_main)
  while syncing; only getblockchaininfo runs, which is also what drives sync-progress detection.
  applyCoreRefreshResult already leaves the balance untouched when balanceOk is false.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/services/network_refresh_service.h

@@ -230,7 +230,10 @@ public:
                                                     bool balanceOk,
                                                     const nlohmann::json& blockInfo,
                                                     bool blockOk);
-    static CoreRefreshResult collectCoreRefreshResult(RefreshRpcGateway& rpc);
+    // includeBalance=false skips z_gettotalbalance (which takes the wallet lock + cs_main) and only
+    // fetches getblockchaininfo — used while syncing, where the balance is incomplete anyway and the
+    // wallet should minimise lock contention with block connection.
+    static CoreRefreshResult collectCoreRefreshResult(RefreshRpcGateway& rpc, bool includeBalance = true);
     static MiningRefreshResult parseMiningRefreshResult(const nlohmann::json& miningInfo,
                                                         bool miningOk,
                                                         const nlohmann::json& localHashrate,