feat(app): scan-mode sync, confirmation-gated documents, single-pass product classification

Fixes reported from APK field testing: DO/Product scan mode was inconsistent
between the camera drawer and documents screen (now one shared provider,
with an orange/green color cue); unconfirmed scans leaked into history with
placeholder data before the user tapped confirm (backend now gates
GET /documents on a new `confirmed` column, flipped only by PUT); and
Product Scan ran the GPU classifier twice, once at upload and again on
review (now a single pass at upload, persisted and read directly by the
editor). Also removes the unused "Hubungkan ke PO" field and fabricated
PO/SO/DO placeholder values from the Product Scan flow, closes out the
per-document-polling and save-recovery tasks (6.1/6.3), and splits several
touched files to stay under the repo's 256-line guideline.

Full detail in docs/iteration-log.md and backend/docs/iteration-log.md.

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

lib/features/camera/camera_drawer_helpers.dart

@@ -0,0 +1,78 @@
+import 'package:flutter/material.dart';
+import '../../config/app_config.dart';
+
+/// Stateless helper functions extracted from [CameraDrawer] to keep that
+/// file under the AGENTS.md §3 256-line threshold (touched in task 8.1).
+/// Contains only UI helpers with no side-effects or state.
+
+Widget buildDrawerSectionHeader(String title) {
+  return Padding(
+    padding: const EdgeInsets.only(left: 16.0, top: 8.0, bottom: 8.0),
+    child: Text(
+      title,
+      style: AppConfig.bodySmall.copyWith(
+        color: Colors.grey.shade400,
+        fontWeight: FontWeight.bold,
+        fontSize: 11,
+        letterSpacing: 1.0,
+      ),
+    ),
+  );
+}
+
+Widget buildDrawerItem({
+  required IconData icon,
+  required String title,
+  required VoidCallback onTap,
+  Color? textColor,
+  Color? iconColor,
+}) {
+  return ListTile(
+    leading: Icon(icon, color: iconColor ?? Colors.black87),
+    title: Text(
+      title,
+      style: AppConfig.bodyLarge.copyWith(
+        color: textColor ?? Colors.black87,
+        fontWeight: FontWeight.w500,
+      ),
+    ),
+    shape: RoundedRectangleBorder(
+      borderRadius: BorderRadius.circular(8),
+    ),
+    onTap: onTap,
+  );
+}
+
+void showDrawerNotImplemented(BuildContext context, String featureName) {
+  ScaffoldMessenger.of(context).showSnackBar(
+    SnackBar(
+      content: Text(' feature coming soon!'),
+      behavior: SnackBarBehavior.floating,
+    ),
+  );
+}
+
+void showDrawerHelpDialog(BuildContext context) {
+  showDialog(
+    context: context,
+    builder: (ctx) => AlertDialog(
+      title: const Text('Tentang Prima Mart'),
+      content: const SingleChildScrollView(
+        child: Text(
+          'www.primafreshmart.com merupakan sarana belanja online dari toko Prima Mart '
+          'yang sudah melayani konsumen selama 10 tahun dan memiliki hampir 1200 gerai '
+          'di Pulau Jawa, Bali dan Sumatera. Inovasi terbaru dari PT. Primafood '
+          'International sebagai bagian dari PT. Charoen Pokphand Indonesia, Tbk.\n\n'
+          'PT. Primafood International\n'
+          'Jl. Ancol Barat VIII no.1, Ancol, Pademangan, Jakarta Utara, DKI Jakarta.',
+        ),
+      ),
+      actions: [
+        TextButton(
+          onPressed: () => Navigator.pop(ctx),
+          child: const Text('Tutup'),
+        )
+      ],
+    ),
+  );
+}