feat: archives file menu, copy (1) naming, excel to pdf, and OCR enrollment validation

- archives: per-file menu (preview/print/download) via icon, right-click, long-press
- documents: copy renames to "name (1).ext" with incrementing collision handling
- documents: convert xls/xlsx/csv to multi-sheet PDF saved in student folder (excel kept)
- students: OCR enrollment scan is review-only with 7-12 grade gate and manual validation modal
- add student: linear OCR progress, SF9/SF10 grade 7-12 validation with auto-fill enrollment

frontend/lib/domain/repositories/document_repository.dart

@@ -1,5 +1,6 @@
 import 'dart:io';
 import 'dart:convert';
+import 'dart:typed_data';
 import 'package:dio/dio.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import '../../core/network/api_constants.dart';
@@ -321,6 +322,34 @@ class DocumentRepository {
     }
   }
 
+  /// Uploads in-memory bytes (e.g. a converted PDF) as a new document in the
+  /// student's folder.
+  Future<void> uploadDocumentBytes({
+    required int studentId,
+    required String documentType,
+    int? requirementId,
+    required String fileName,
+    required Uint8List bytes,
+  }) async {
+    try {
+      final options = await _getAuthOptions();
+      final formData = FormData.fromMap({
+        'studentId': studentId,
+        'documentType': documentType,
+        if (requirementId != null) 'requirementId': requirementId,
+        'document': MultipartFile.fromBytes(
+          bytes,
+          filename: fileName,
+          contentType: DioMediaType('application', 'pdf'),
+        ),
+      });
+      await _dio.post('/documents/upload', data: formData, options: options);
+    } on DioException catch (e) {
+      final msg = e.response?.data?['message'] ?? 'Failed to upload document.';
+      throw Exception(msg);
+    }
+  }
+
   Future<void> bulkDeleteDocuments(List<int> ids) async {
     try {
       final options = await _getAuthOptions();

frontend/lib/domain/repositories/student_repository.dart

@@ -35,6 +35,33 @@ class StudentPage {
   }
 }
 
+/// A single enrollment record extracted from an SF9/SF10 OCR scan.
+class OcrEnrollmentRecord {
+  final String gradeLevel;
+  final String section;
+  final String schoolYear;
+  final String adviserName;
+  final String semester;
+
+  const OcrEnrollmentRecord({
+    required this.gradeLevel,
+    required this.section,
+    required this.schoolYear,
+    this.adviserName = '',
+    this.semester = '',
+  });
+
+  factory OcrEnrollmentRecord.fromJson(Map<String, dynamic> json) {
+    return OcrEnrollmentRecord(
+      gradeLevel: (json['gradeLevel'] as String?) ?? '',
+      section: (json['section'] as String?) ?? '',
+      schoolYear: (json['schoolYear'] as String?) ?? '',
+      adviserName: (json['adviserName'] as String?) ?? '',
+      semester: (json['semester'] as String?) ?? '',
+    );
+  }
+}
+
 class StudentRepository {
   final Dio _dio = ApiConstants.createDio();
   final FlutterSecureStorage _storage = const FlutterSecureStorage();
@@ -441,14 +468,18 @@ class StudentRepository {
   // ----------------------------------------------------------------
   // Manual SF9/SF10 OCR Scan Enrollment
   // ----------------------------------------------------------------
-  Future<Map<String, dynamic>> scanEnrollmentFromSF(int studentId) async {
+  Future<List<OcrEnrollmentRecord>> scanEnrollmentFromSF(int studentId) async {
     try {
       final options = await _getAuthOptions();
       final response = await _dio.post(
         '/students/$studentId/ocr-enrollment',
         options: options,
       );
-      return response.data as Map<String, dynamic>;
+      final data = response.data as Map<String, dynamic>;
+      final records = (data['data'] as Map<String, dynamic>?)?['records'] as List?;
+      return (records ?? [])
+          .map((r) => OcrEnrollmentRecord.fromJson(r as Map<String, dynamic>))
+          .toList();
     } on DioException catch (e) {
       final msg = e.response?.data?['message'] ?? 'Failed to scan SF10/SF9 for enrollment.';
       throw Exception(msg);