feat: blockchain rescan via daemon restart + status bar progress

- Fix z_importwallet to use full path instead of filename only
- Add rescanBlockchain() method that restarts daemon with -rescan flag
- Track rescan progress via daemon output parsing and getrescaninfo RPC
- Display rescan progress in status bar with animated indicator when starting
- Improve dark theme card contrast: lighter surface-variant, tinted borders, stronger rim-light

src/data/wallet_state.h

@@ -113,6 +113,11 @@ struct SyncInfo {
     bool syncing = false;
     std::string best_blockhash;
     
+    // Rescan state (detected from daemon output)
+    bool rescanning = false;
+    float rescan_progress = 0.0f;  // 0.0 - 1.0
+    std::string rescan_status;     // e.g. "Rescanning... 25%"
+    
     bool isSynced() const { return !syncing && blocks > 0 && blocks >= headers - 2; }
 };