feat: track shielded send txids via z_viewtransaction

Extract txids from completed z_sendmany operations and store in
send_txids_ so pure shielded sends are discoverable. The network
thread includes them in the enrichment set, calls z_viewtransaction,
caches results in viewtx_cache_, and removes them from send_txids_.

src/app_network.cpp

@@ -437,6 +437,9 @@ void App::refreshData()
     // Snapshot viewtx cache for the worker thread
     auto viewtxCacheSnap = viewtx_cache_;
 
+    // Snapshot send txids so the worker can include them in enrichment
+    auto sendTxidsSnap = send_txids_;
+
     // Single consolidated worker task — all RPC calls happen back-to-back
     // on a single thread with no inter-task queue overhead.
     worker_->post([this, doAddresses, doPeers, doEncrypt, doTransactions,
@@ -444,7 +447,8 @@ void App::refreshData()
                    fullyEnriched = std::move(fullyEnriched),
                    cachedConfirmedTxns = std::move(cachedConfirmedTxns),
                    cachedConfirmedIds = std::move(cachedConfirmedIds),
-                   viewtxCacheSnap = std::move(viewtxCacheSnap)]() -> rpc::RPCWorker::MainCb {
+                   viewtxCacheSnap = std::move(viewtxCacheSnap),
+                   sendTxidsSnap = std::move(sendTxidsSnap)]() -> rpc::RPCWorker::MainCb {
         // ================================================================
         // Phase 1: Balance + blockchain info
         // ================================================================
@@ -596,6 +600,13 @@ void App::refreshData()
                 }
             }
 
+            // Include txids from completed z_sendmany operations so that
+            // pure shielded sends (which don't appear in listtransactions
+            // or z_listreceivedbyaddress) are discoverable.
+            for (const auto& txid : sendTxidsSnap) {
+                knownTxids.insert(txid);
+            }
+
             // Phase 3c: detect shielded sends via z_viewtransaction
             // Check the in-memory viewtx cache first; only make RPC calls
             // for txids we haven't seen before.
@@ -858,6 +869,8 @@ void App::refreshData()
                 // Merge new z_viewtransaction results into the persistent cache
                 for (auto& [txid, entry] : newViewTxEntries) {
                     viewtx_cache_[txid] = std::move(entry);
+                    // Once cached, no need to keep in send_txids_
+                    send_txids_.erase(txid);
                 }
 
                 // Rebuild confirmed transaction cache: txns with >= 10