feat(lite): M2b-3 — background refresh worker + App::update hook

- LiteWalletController owns a background std::thread worker that, once a wallet is ready,
  refreshes every ~4s and publishes a copyable LiteWalletAppRefreshModel under a mutex.
  Worker auto-starts on lifecycle-ready and is stopped+joined in the destructor. status_
  is written only on the main thread; walletOpen_/syncStarted_ are atomic.
- App::update() calls takeRefreshedModel() and applies it into state_ on the main thread
  (WalletState is non-copyable, so the model crosses the thread boundary, not the state),
  so the existing Balance/Receive/Transactions tabs populate from lite data.
- refreshWalletState() refactored onto refreshModel() (pure, worker-safe).
- testLiteWalletControllerWorkerProducesModel verifies the worker publishes a populated
  model (stable across repeated runs). Builds clean in all configs.

Real-backend smoke (lite_smoke --refresh now runs real output through the parsers) found
two integration bugs, documented in the plan for follow-up:
- syncstatus parser requires synced_blocks/total_blocks but the real idle response is
  {"syncing":"false"} (string), so it fails to parse when not actively syncing.
- the first data query (balance/list) blocks on a full chain sync, which would hang the
  worker's shutdown join — needs a cancel/timeout path.

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

docs/lite-wallet-implementation-plan-v2-2026-06-04.md

@@ -95,7 +95,12 @@ Each milestone is independently demoable and gated by a fake-backend test. Order
 > - ℹ️ The fetch/parse/assemble pipeline already exists and works: `LiteWalletGateway::refresh()` → `LiteWalletRefreshBundle` → `mapLiteWalletRefreshBundle()` → `LiteWalletAppRefreshModel`. M2 just needed the final `→ WalletState` hop (above) plus live wiring.
 > - ✅ **M2b-1 — shared-bridge refactor (done).** `litelib` is a global singleton and every `LiteClientBridge` calls `litelib_shutdown()` on destruction, so services must not each own one. `LiteWalletLifecycleService`, `LiteWalletGateway`, and `LiteSyncService` now take a **non-owning `LiteClientBridge*`**; `LiteWalletController` owns the single bridge and passes `&bridge_`. Builds clean in all configs; existing tests stay green.
 > - ✅ **M2b-2 — sync + controller refresh (done + tested).** `LiteSyncService::startSync` now executes the `sync` command (was a stub). `LiteWalletController` gained `startSync()` (auto-invoked when a wallet becomes ready) and `refreshWalletState(WalletState&)` which polls `syncstatus`, runs `gateway.refresh()`, maps the bundle, and applies it into `WalletState`. `testLiteWalletControllerRefreshPopulatesState()` drives the full path against the real-shape fake (balances/addresses/transactions/sync populated; no-op when no wallet open). The fake harness now returns command-shaped JSON per `tests/fixtures/lite/result_parsers.json`. (Surfaced a real bug: `info` requires `latest_block_height`, and the gateway aborts the whole refresh on the first command's parse failure — fixed in the fake; worth noting the gateway's abort-on-first-failure is fragile against partial backend responses.)
-> - ⏳ **M2b-3 — threaded App hook (remaining).** Drive `refreshWalletState` from a controller-owned background worker (mirror `NetworkRefreshService`/`RefreshScheduler`): worker produces a copyable `LiteWalletAppRefreshModel`; `App::update()` applies it into `state_` on the main thread (WalletState is non-copyable, so pass the model, not the state, across threads). `litelib_execute` is `catch_unwind`-safe so the worker won't abort the app. Also: per-address balances (notes-correlation) and a real-backend refresh smoke (the real backend's JSON shapes may differ from the hand-built fixture).
+> - ✅ **M2b-3 — threaded App hook (done + tested).** `LiteWalletController` owns a background worker (`std::thread`) that, once a wallet is ready, refreshes every ~4s and publishes a copyable `LiteWalletAppRefreshModel` under a mutex; `App::update()` calls `takeRefreshedModel()` and applies it into `state_` on the main thread (WalletState is non-copyable, so the model crosses the thread boundary, not the state). Worker auto-starts on lifecycle-ready and is stopped+joined in the controller destructor. `status_` is written only on the main thread to avoid races; `walletOpen_`/`syncStarted_` are atomic. `testLiteWalletControllerWorkerProducesModel()` opens a wallet and asserts the worker publishes a populated model (stable across repeated runs). Builds clean in all configs.
+> **Real-backend refresh smoke (2026-06-04): ran `lite_smoke --create --refresh` against the live backend — found two real bugs** the fake/fixture couldn't (smoke now links `lite_result_parsers` and runs each command's real output through the parser):
+> 1. **OPEN — `syncstatus` parser mismatch.** `parseLiteSyncStatusResponse` hard-requires `synced_blocks`/`total_blocks`, but the real backend (per `commands.rs:83-87`) returns **idle = `{"syncing":"false"}`** (string!) and only **in-progress = `{"syncing":"true","synced_blocks":N,"total_blocks":M}`**. So syncstatus fails to parse whenever the wallet isn't actively syncing → sync/progress never updates in the real app. Fix: read `syncing` as a string, make the block fields optional. (info/balance/addresses parsers verified OK against real output.)
+> 2. **OPEN — first data query blocks on a full chain sync.** `execute("balance"/"list")` on a fresh wallet triggers a synchronous multi-million-block sync (observed "Syncing 1.76M/2.99M…"). On the M2b-3 worker thread that means the controller's destructor `join()` would hang at app shutdown. Needs: a cancel/timeout path for in-flight refresh (e.g., don't block shutdown on the worker), and likely gating data fetches until sync has progressed. **This is the main blocker for a usable real lite wallet** and should lead M2 polish / M3.
+>
+> - ⏳ **Remaining for M2 polish:** fix the syncstatus parser (above), address the blocking-sync/worker-shutdown issue (above), per-address balances (notes-correlation; currently aggregate-only), and harden the gateway's abort-on-first-failure (skip-and-continue per command).
 - Implement `LiteSyncService::startSync` (replace the "not implemented" stub) + a background worker polling `syncstatus`, mirroring `NetworkRefreshService`/`RefreshScheduler` (enqueue → worker → apply on main thread).
 - Drive `LiteWalletGateway` refresh (info/height/balance/addresses/notes/list/transactions) through `lite_result_parsers` → `lite_wallet_state_mapper` → `App` `WalletState` (`privateBalance`, `transparentBalance`, `addresses`, `transactions`, `sync`).
 - Hook the controller into `App::update()`'s refresh dispatch alongside (not inside) the full-node path.