新增阅读器功能，待优化

lib/utils/reader_url_generator.dart

@@ -0,0 +1,69 @@
+import 'dart:convert';
+import '../service/book_server.dart';
+import 'color_converter.dart';
+
+/// 生成 foliate-js 阅读器 URL
+String generateReaderUrl({
+  required String fileUrl,
+  String cfi = '',
+  required String backgroundColor,
+  required String textColor,
+  bool isDarkMode = false,
+}) {
+  final indexHtmlPath = 'http://127.0.0.1:${Server().port}/foliate-js/index.html';
+
+  final jsBg = convertDartColorToJs(backgroundColor);
+  final jsTc = convertDartColorToJs(textColor);
+
+  final style = {
+    'fontSize': 100,         // 100 = base 100%
+    'fontName': '',
+    'fontPath': '',
+    'fontWeight': 400,
+    'letterSpacing': 0,
+    'spacing': 1.6,
+    'paragraphSpacing': 0.6,
+    'textIndent': 2,
+    'fontColor': '#$jsTc',
+    'backgroundColor': '#$jsBg',
+    'topMargin': 25,
+    'bottomMargin': 25,
+    'sideMargin': 15,
+    'justify': true,
+    'hyphenate': false,
+    'pageTurnStyle': 'slide',
+    'maxColumnCount': 1,
+    'columnThreshold': 3,
+    'writingMode': 'horizontal-tb',
+    'textAlign': 'justify',
+    'backgroundImage': '',
+    'bgimgBlur': 0,
+    'bgimgOpacity': 1.0,
+    'bgimgFit': 'cover',
+    'allowScript': false,
+    'customCSS': '',
+    'customCSSEnabled': false,
+    'useBookStyles': true,
+    'headingFontSize': 130,
+    'codeHighlightTheme': 'atom-one-light',
+  };
+
+  final readingRules = {
+    'convertChineseMode': 'none',
+    'bionicReadingMode': false,
+  };
+
+  final params = {
+    'importing': false,
+    'url': fileUrl,
+    'initialCfi': cfi,
+    'style': style,
+    'readingRules': readingRules,
+  };
+
+  final queryParts = params.entries
+      .map((e) => '${e.key}=${Uri.encodeComponent(jsonEncode(e.value))}')
+      .join('&');
+
+  return '$indexHtmlPath?$queryParts';
+}