Open the cash drawer for real, and persist the back-office route

Cash drawer
- openCashDrawer was a debugPrint. The drawer never opened.
- It cannot go through the PDF pipeline: a PDF is rendered by the platform
  driver, which will not pass raw ESC/POS bytes to the device. So it goes over
  a socket instead — nearly every network thermal printer listens on 9100 and
  forwards whatever arrives straight to the print head, which makes the whole
  protocol five bytes.
- Printer IP and port are configurable in Settings with a Test button that
  saves and fires immediately, because a drawer that does not open is
  indistinguishable from one that is not wired up.
- Every failure explains itself: unreachable, refused, or simply not
  configured — which is the honest state for a USB printer, since there is no
  raw path to one from Flutter.
- Now fires only on a cash tender. A card-only sale that pops the drawer is a
  shrinkage risk, and it is the first thing a shop notices.

Back-office route
- Host, port, TLS and transport persist to the database; username, password
  and API key go to the platform keystore (Keychain / Credential Manager /
  Android Keystore). Writing credentials into SQLite would put them in the
  same file as the bills, on a machine behind a shop counter.
- Loaded at startup. Previously the dialog wrote settings that were silently
  ignored on the next launch, which reads exactly like they never saved — and
  credentials retyped every morning end up on a sticky note instead.
- A saved route never overwrites the terminal's store or terminal id. Those
  belong to the device, and re-pointing a till at a different broker must not
  change who it is, or its bills and presence records stop lining up.

Tests: 168 -> 176. The drawer test stands up a real socket server and asserts
the exact bytes arrive. The config test asserts no credential appears anywhere
in the meta table while the non-secret settings do.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

lib/presentation/modules/providers/printer_settings.dart

@@ -15,6 +15,8 @@ class PrinterSettings {
     this.printerName,
     this.autoPrint = false,
     this.openDrawer = true,
+    this.drawerHost,
+    this.drawerPort = 9100,
   });
 
   /// Target passed to `directPrintPdf`. Null means "use the system default".
@@ -31,7 +33,16 @@ class PrinterSettings {
 
   final bool openDrawer;
 
+  /// IP address of the receipt printer the drawer is wired to.
+  ///
+  /// Separate from [printerUrl] because that is an opaque platform handle for
+  /// the PDF driver, which cannot carry raw ESC/POS bytes. The drawer kick
+  /// needs a socket, so it needs an address.
+  final String? drawerHost;
+  final int drawerPort;
+
   bool get hasPrinter => printerUrl != null;
+  bool get hasDrawer => (drawerHost ?? '').isNotEmpty;
 
   PrinterSettings copyWith({
     String? printerUrl,
@@ -39,12 +50,16 @@ class PrinterSettings {
     bool clearPrinter = false,
     bool? autoPrint,
     bool? openDrawer,
+    String? drawerHost,
+    int? drawerPort,
   }) {
     return PrinterSettings(
       printerUrl: clearPrinter ? null : (printerUrl ?? this.printerUrl),
       printerName: clearPrinter ? null : (printerName ?? this.printerName),
       autoPrint: autoPrint ?? this.autoPrint,
       openDrawer: openDrawer ?? this.openDrawer,
+      drawerHost: drawerHost ?? this.drawerHost,
+      drawerPort: drawerPort ?? this.drawerPort,
     );
   }
 }
@@ -69,6 +84,8 @@ class PrinterSettingsController extends StateNotifier<PrinterSettings> {
     final name = await dao.meta(MetaKeys.printerName);
     final autoPrint = await dao.meta(MetaKeys.autoPrint);
     final openDrawer = await dao.meta(MetaKeys.openDrawer);
+    final drawerHost = await dao.meta(MetaKeys.drawerHost);
+    final drawerPort = await dao.meta(MetaKeys.drawerPort);
 
     if (!mounted) return;
 
@@ -77,6 +94,8 @@ class PrinterSettingsController extends StateNotifier<PrinterSettings> {
       printerName: name,
       autoPrint: autoPrint == '1',
       openDrawer: openDrawer != '0',
+      drawerHost: drawerHost,
+      drawerPort: int.tryParse(drawerPort ?? '') ?? 9100,
     );
   }
 
@@ -120,6 +139,18 @@ class PrinterSettingsController extends StateNotifier<PrinterSettings> {
     if (!mounted) return;
     state = state.copyWith(openDrawer: value);
   }
+
+  /// Points the drawer kick at a printer.
+  ///
+  /// A blank host disables it — which is the honest state for a USB printer,
+  /// since there is no raw path to one from Flutter.
+  Future<void> setDrawerAddress(String host, int port) async {
+    final dao = _ref.read(localStoreProvider).catalogue;
+    await dao.setMeta(MetaKeys.drawerHost, host.trim());
+    await dao.setMeta(MetaKeys.drawerPort, '$port');
+    if (!mounted) return;
+    state = state.copyWith(drawerHost: host.trim(), drawerPort: port);
+  }
 }
 
 final printerSettingsProvider =