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/data/local/app_database.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/foundation.dart';
 import 'package:path/path.dart' as p;
-import 'package:sqflite/sqflite.dart';
 import 'package:sqflite_common_ffi/sqflite_ffi.dart';
 
 /// SQLite database for the terminal.
@@ -14,7 +13,7 @@ class AppDatabase {
   static final AppDatabase instance = AppDatabase._();
 
   static const String _fileName = 'nearle_pos.db';
-  static const int _version = 3;
+  static const int _version = 4;
 
   Database? _db;
 
@@ -70,6 +69,7 @@ class AppDatabase {
               'ALTER TABLE ${Tables.products} ADD COLUMN hsn_code TEXT',
             );
           }
+          if (from < 4) await _upgradeToV4(db, from: from);
         },
       ),
     );
@@ -238,18 +238,7 @@ class AppDatabase {
     ''');
 
     // -------------------------------------------------------------- syncLog
-    await db.execute('''
-      CREATE TABLE ${Tables.syncLog} (
-        id          TEXT PRIMARY KEY,
-        type        TEXT    NOT NULL,
-        status      TEXT    NOT NULL,
-        created_at  INTEGER NOT NULL,
-        synced_at   INTEGER,
-        summary     TEXT    NOT NULL,
-        error       TEXT,
-        attempts    INTEGER NOT NULL DEFAULT 0
-      )
-    ''');
+    await db.execute(_createSyncLog);
 
     // ------------------------------------------------------------- archive
     await db.execute(_createDayArchive);
@@ -264,14 +253,61 @@ class AppDatabase {
   }
 }
 
-/// Running totals per business day.
+/// Moves the schema to v4.
+///
+/// Adds the payload column the sync log needs to be usable at all, and re-keys
+/// the day archive by cashier so a shift report can be scoped to whoever is
+/// settling their till. Existing archived rows predate per-cashier attribution,
+/// so they are folded under an empty name rather than guessed at.
+Future<void> _upgradeToV4(Database db, {required int from}) async {
+  // A v1 database had no sync_log payload column; v2+ did not either.
+  await db.execute(
+    'ALTER TABLE ${Tables.syncLog} ADD COLUMN payload_json TEXT',
+  );
+
+  await db.execute('ALTER TABLE ${Tables.dayArchive} RENAME TO _day_archive_v3');
+  await db.execute(_createDayArchive);
+  await db.execute('''
+    INSERT INTO ${Tables.dayArchive} (
+      business_date, cashier_name, bill_count, item_count, gross_sales,
+      tax_collected, discount_given, round_off, points_issued,
+      points_redeemed, payments_json, first_bill_at, last_bill_at,
+      synced_bills
+    )
+    SELECT
+      business_date, '', bill_count, item_count, gross_sales,
+      tax_collected, discount_given, round_off, points_issued,
+      points_redeemed, payments_json, first_bill_at, last_bill_at,
+      synced_bills
+    FROM _day_archive_v3
+  ''');
+  await db.execute('DROP TABLE _day_archive_v3');
+}
+
+const String _createSyncLog = '''
+  CREATE TABLE sync_log (
+    id           TEXT PRIMARY KEY,
+    type         TEXT    NOT NULL,
+    status       TEXT    NOT NULL,
+    created_at   INTEGER NOT NULL,
+    synced_at    INTEGER,
+    summary      TEXT    NOT NULL,
+    error        TEXT,
+    attempts     INTEGER NOT NULL DEFAULT 0,
+    payload_json TEXT
+  )
+''';
+
+/// Running totals per business day and cashier.
 ///
 /// Synced orders are deleted from the terminal, so their figures are folded in
 /// here first — otherwise "Bills Today" would collapse to zero the moment a
-/// mid-shift sync ran.
+/// mid-shift sync ran. Keyed by cashier as well as date, because once the
+/// orders are gone this row is the only thing left to settle a till against.
 const String _createDayArchive = '''
   CREATE TABLE day_archive (
-    business_date   TEXT PRIMARY KEY,
+    business_date   TEXT    NOT NULL,
+    cashier_name    TEXT    NOT NULL DEFAULT '',
     bill_count      INTEGER NOT NULL DEFAULT 0,
     item_count      REAL    NOT NULL DEFAULT 0,
     gross_sales     REAL    NOT NULL DEFAULT 0,
@@ -283,7 +319,8 @@ const String _createDayArchive = '''
     payments_json   TEXT    NOT NULL DEFAULT '{}',
     first_bill_at   INTEGER,
     last_bill_at    INTEGER,
-    synced_bills    INTEGER NOT NULL DEFAULT 0
+    synced_bills    INTEGER NOT NULL DEFAULT 0,
+    PRIMARY KEY (business_date, cashier_name)
   )
 ''';