feat(chat): harvest chat memos on the lite variant (lite receive)

The full-node receive harvest works off z_viewtransaction; the lite wallet's
transactions come from the backend instead, so lite chat receive was unwired.

App::ingestLiteChatMemos runs after each lite refresh: the backend lists one
entry per received (non-change) note — same txid, distinct position + decoded
UTF-8 memo — so a chat tx yields two entries (header + payload). Group the
Receive-kind notes by txid, feed them through the SAME extractHushChatTransaction
Metadata parser (now order-tolerant, so the daemon's output shuffle is a non-issue),
and thread the result into ChatService. The store dedups (txid+position), so
re-listing every refresh is harmless.

This closes the lite variant's chat loop end-to-end: identity (exportSeed), DB
unlock/load, receive (here), UI, and send (broadcastChatMemosLite). Gated by
DRAGONX_ENABLE_CHAT (default OFF). Verified: Linux + Windows build with chat ON,
ctest 100%, hygiene clean; caches restored to OFF.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app.cpp

@@ -682,6 +682,9 @@ void App::update()
         wallet::LiteWalletAppRefreshModel liteModel;
         if (lite_wallet_->takeRefreshedModel(liteModel)) {
             wallet::applyLiteRefreshModelToWalletState(liteModel, state_);
+            // HushChat (lite): harvest chat memos from the refreshed transactions and thread them
+            // (no-op when the feature is off or no identity; the store dedups across refreshes).
+            ingestLiteChatMemos(liteModel);
         }
         // Deliver a completed async send/shield result to the waiting send_tab callback.
         wallet::LiteBroadcastResult broadcast;