Fix billing data integrity, sale atomicity and stock safety

Bills were persisted correctly but read back wrong. The read path rebuilt a
cart from its lines alone, dropping bill-level discounts and loyalty, so every
figure derived from a stored bill was overstated: the upload payload, the day
archive and the shift report. A discounted 529 bill read back as 620.

Money and data integrity
- order_dao: restore bill_discount and points_redeemed when rebuilding a cart;
  keep the reconstruction tier-less so the membership discount is not applied
  twice. Trust the recorded total and points via SaleTransaction.storedTotal.
- checkout_sale + order_dao.commitSale: write the bill, its stock movement and
  the loyalty update in one transaction. Previously a failure part-way through
  left a persisted bill the cashier believed had failed, inviting a duplicate.
- checkout_sale: re-check every line against live stock. A parked bill resumed
  after its stock was sold passed validation and oversold.
- catalogue_dao: allocate the invoice sequence in one transaction; the previous
  read-modify-write could hand two sales the same number and fail UNIQUE.
- local_store: replay unsynced sales after a catalogue import, so a mid-shift
  re-import cannot restore stock that has already been sold.
- payment_controller: stamp the signed-in operator on the bill instead of the
  hardcoded seed session, and pass the terminal id through.
- cart: reconcile per-slab GST against the bill total so the parts sum to the
  whole on a tax invoice.

Sync and reporting
- sync_repository: drain unsynced bills in a loop rather than silently capping
  at one page; stop on rejection so rejected rows cannot loop forever.
- sync_log_dao (new): persist the sync history to the sync_log table, which the
  schema already defined but nothing used. It was in memory, so the only record
  that bills had been uploaded died at restart.
- Scope shift reports by cashier. day_archive is re-keyed to
  (business_date, cashier_name) so a till stays settleable after its bills are
  uploaded and deleted. Schema v4 with a migration that carries v3 rows across.

Input and UI
- barcode_service: consume machine-paced keystrokes so a scan cannot also land
  in the focused field, and raise the bar to 60ms/char while a text field has
  focus so typing a mobile number is not read as a scan. Clock and focus check
  injected so the behaviour is testable.
- primary_button: make the label flexible; label plus trailing total overflowed
  the Charge button by up to 131px.
- app_router: redirect instead of null-casting when the receipt route is
  entered without its transaction.
- customer_repository: reduce the search query to digits so a punctuated mobile
  number matches.

Cleanup
- Remove TransactionRepository.save, CustomerRepository.recordSale and
  OrderDao.insertOrder, all superseded by commitSale.
- dart fix across the tree; 251 analyzer issues down to 3 info-level.

Tests: 23 passing / 15 failing -> 90 passing. Fixed the two defects that broke
the existing suite (containsAll type argument, reset() needing a catalogue) and
deleted the leftover template test. Added coverage for the order round trip,
the day archive after a real sync, stock safety, checkout atomicity, the v3->v4
migration, scanner-versus-human input, and an app-level smoke test that renders
every module.

Note: bills already uploaded with a discount went up overstated. This stops it
happening again but does not correct historical server data.

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

lib/presentation/receipt/screens/receipt_screen.dart

@@ -58,7 +58,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
             content: Text(
               'Printer did not respond — use Print to send it again.',
             ),
-          ));
+          ),);
       }
     });
 
@@ -112,7 +112,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
                         height: 480,
                         child: ReceiptPreview(transaction: txn),
                       ),
-                    ]),
+                    ],),
                   )
                 : Row(
                     crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -148,7 +148,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
                 shape: BoxShape.circle,
               ),
               child: const Icon(Icons.check_rounded,
-                  size: 44, color: AppColors.success),
+                  size: 44, color: AppColors.success,),
             )
                 .animate()
                 .scale(
@@ -161,7 +161,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
           const SizedBox(height: AppSpacing.xl),
           Text('Sale complete',
               textAlign: TextAlign.center,
-              style: context.text.headlineMedium),
+              style: context.text.headlineMedium,),
           const SizedBox(height: AppSpacing.xs),
           Text(
             '${txn.invoiceNumber}  ·  ${Formatters.dateTime(txn.createdAt)}',
@@ -172,7 +172,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
           const SizedBox(height: AppSpacing.xxl),
           Container(
             padding: const EdgeInsets.all(AppSpacing.xl),
-            decoration: BoxDecoration(
+            decoration: const BoxDecoration(
               color: AppColors.primarySurface,
               borderRadius: AppRadius.brLg,
             ),
@@ -188,12 +188,12 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
               _row('Paid via', txn.paymentSummary),
               if (txn.changeDue > 0)
                 _row('Change returned', Formatters.money(txn.changeDue),
-                    highlight: AppColors.success),
+                    highlight: AppColors.success,),
               _row('Items', '${txn.cart.lineCount}'),
               if (txn.customer != null) ...[
                 _row('Customer', txn.customer!.name),
                 _row('Points earned', '+${txn.pointsEarned}',
-                    highlight: AppColors.success),
+                    highlight: AppColors.success,),
                 if (txn.pointsRedeemed > 0)
                   _row('Points redeemed', '-${txn.pointsRedeemed}'),
               ],
@@ -203,7 +203,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
                   Formatters.money(txn.cart.totalSavings),
                   highlight: AppColors.success,
                 ),
-            ]),
+            ],),
           ),
 
           const SizedBox(height: AppSpacing.xxl),
@@ -256,7 +256,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
                               content: Text(
                                 'Could not open WhatsApp on this device.',
                               ),
-                            ));
+                            ),);
                         },
                 ),
               ),
@@ -314,7 +314,7 @@ class _ReceiptScreenState extends ConsumerState<ReceiptScreen> {
                 style: const TextStyle(
                   fontSize: 13.5,
                   color: AppColors.textSecondary,
-                )),
+                ),),
             Text(
               value,
               style: TextStyle(