refactor: migrate to flutter_math_fork and markdown_widget for enhanced markdown capabilities

- Replaced flutter_markdown_plus with flutter_math_fork to improve mathematical rendering within markdown content.
- Integrated markdown_widget for better markdown processing and rendering, enhancing overall user experience.
- Updated the markdown configuration to utilize the new packages, ensuring maintainability and adaptability of markdown features.
- Refactored the streaming markdown widget to accommodate the new markdown processing logic, improving code clarity and performance.

lib/shared/widgets/markdown/markdown_latex.dart

@@ -0,0 +1,101 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_math_fork/flutter_math.dart';
+import 'package:markdown/markdown.dart' as m;
+import 'package:markdown_widget/markdown_widget.dart';
+
+import '../../theme/theme_extensions.dart';
+
+const String _latexTag = 'latex';
+
+/// Provides LaTeX parsing support for markdown_widget.
+class ConduitLatex {
+  const ConduitLatex();
+
+  /// Returns the inline syntax used to identify LaTeX segments.
+  m.InlineSyntax syntax() => _LatexSyntax();
+
+  /// Returns the span generator that renders LaTeX expressions.
+  SpanNodeGeneratorWithTag generator({required bool isDark}) {
+    return SpanNodeGeneratorWithTag(
+      tag: _latexTag,
+      generator: (element, config, visitor) {
+        return _LatexNode(
+          attributes: element.attributes,
+          rawText: element.textContent,
+          config: config,
+          isDark: isDark,
+        );
+      },
+    );
+  }
+}
+
+class _LatexSyntax extends m.InlineSyntax {
+  _LatexSyntax() : super(r'(\$\$[\s\S]+?\$\$)|(\$[^\n]+?\$)');
+
+  @override
+  bool onMatch(m.InlineParser parser, Match match) {
+    final raw = match.input.substring(match.start, match.end);
+    final element = m.Element.text(_latexTag, raw);
+    if (raw.startsWith(r'$$') && raw.endsWith(r'$$') && raw.length > 4) {
+      element.attributes['content'] = raw.substring(2, raw.length - 2);
+      element.attributes['isInline'] = 'false';
+    } else if (raw.startsWith(r'$') && raw.endsWith(r'$') && raw.length > 2) {
+      element.attributes['content'] = raw.substring(1, raw.length - 1);
+      element.attributes['isInline'] = 'true';
+    } else {
+      element.attributes['content'] = raw;
+      element.attributes['isInline'] = 'true';
+    }
+    parser.addNode(element);
+    return true;
+  }
+}
+
+class _LatexNode extends SpanNode {
+  _LatexNode({
+    required this.attributes,
+    required this.rawText,
+    required this.config,
+    required this.isDark,
+  });
+
+  final Map<String, String> attributes;
+  final String rawText;
+  final MarkdownConfig config;
+  final bool isDark;
+
+  @override
+  InlineSpan build() {
+    final content = attributes['content']?.trim();
+    final isInline = attributes['isInline'] == 'true';
+    final baseStyle = (parentStyle ?? config.p.textStyle).copyWith(
+      color:
+          (parentStyle ?? config.p.textStyle).color ??
+          (isDark ? Colors.white : Colors.black),
+    );
+
+    if (content == null || content.isEmpty) {
+      return TextSpan(text: rawText, style: baseStyle);
+    }
+
+    final latexWidget = Math.tex(
+      content,
+      mathStyle: MathStyle.text,
+      textStyle: baseStyle,
+      textScaleFactor: 1,
+      onErrorFallback: (error) {
+        return Text(rawText, style: baseStyle.copyWith(color: Colors.red));
+      },
+    );
+
+    final widget = isInline
+        ? latexWidget
+        : Padding(
+            padding: const EdgeInsets.symmetric(vertical: Spacing.xs),
+            child: Center(child: latexWidget),
+          );
+
+    return WidgetSpan(alignment: PlaceholderAlignment.middle, child: widget);
+  }
+}