fix(lite): parse real syncstatus shapes (idle vs in-progress)

The real backend returns syncstatus as idle {"syncing":"false"} (string) or in-progress
{"syncing":"true","synced_blocks":N,"total_blocks":M} (commands.rs:83-87), but
parseLiteSyncStatusResponse hard-required the block fields and failed whenever the wallet
wasn't actively syncing — so sync/progress never updated in the real app.

- Read "syncing" as a string; require synced_blocks/total_blocks only when syncing=true;
  idle => complete, synced/total 0.
- fake_lite_backend syncstatus now uses the real "syncing":"true" shape.
- testLiteSyncStatusParserRealShapes covers idle, in-progress, and missing-counts-while-syncing.
- Verified against the live backend via lite_smoke --refresh (syncstatus parse_ok=1).

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

tests/fake_lite_backend.h

@@ -65,8 +65,8 @@ inline char* liteFakeExecute(const char* command, const char*)
     if (command) {
         const char* c = command;
         if (std::strcmp(c, "sync") == 0) return liteFakeDup("{\"result\":\"success\"}");
-        if (std::strcmp(c, "syncstatus") == 0)
-            return liteFakeDup("{\"synced_blocks\":1000,\"total_blocks\":1000}");
+        if (std::strcmp(c, "syncstatus") == 0)  // real backend shape: "syncing" is a string
+            return liteFakeDup("{\"syncing\":\"true\",\"synced_blocks\":1000,\"total_blocks\":1000}");
         if (std::strcmp(c, "balance") == 0)
             return liteFakeDup("{\"tbalance\":100000000,\"zbalance\":200000000,\"unconfirmed\":50000000,"
                                "\"verified_zbalance\":180000000,\"spendable_zbalance\":170000000}");