refactor(markdown): Replace markdown library with gpt_markdown and update styling

lib/shared/widgets/markdown/streaming_markdown_widget.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 
-import '../../theme/theme_extensions.dart';
 import 'markdown_config.dart';
 import 'markdown_preprocessor.dart';
 
@@ -70,71 +69,62 @@ class StreamingMarkdownWidget extends StatelessWidget {
     specialBlocks.sort((a, b) => a.start.compareTo(b.start));
 
     Widget buildMarkdown(String data) {
-      return ConduitMarkdown.buildBlock(
+      return ConduitMarkdown.build(
         context: context,
         data: data,
         onTapLink: onTapLink,
-        selectable: false,
         imageBuilderOverride: imageBuilderOverride,
       );
     }
 
+    Widget result;
+
     if (specialBlocks.isEmpty) {
-      return SelectionArea(
-        child: Theme(
-          data: Theme.of(context).copyWith(
-            textSelectionTheme: TextSelectionThemeData(
-              cursorColor: context.conduitTheme.buttonPrimary,
-            ),
-          ),
-          child: buildMarkdown(normalized),
-        ),
+      result = buildMarkdown(normalized);
+    } else {
+      final children = <Widget>[];
+      var currentIndex = 0;
+      for (final block in specialBlocks) {
+        // Skip overlapping blocks
+        if (block.start < currentIndex) continue;
+
+        final before = normalized.substring(currentIndex, block.start);
+        if (before.trim().isNotEmpty) {
+          children.add(buildMarkdown(before));
+        }
+
+        switch (block.type) {
+          case _BlockType.mermaid:
+            children.add(
+              ConduitMarkdown.buildMermaidBlock(context, block.content),
+            );
+          case _BlockType.chartJs:
+            children.add(
+              ConduitMarkdown.buildChartJsBlock(context, block.content),
+            );
+        }
+
+        currentIndex = block.end;
+      }
+
+      final tail = normalized.substring(currentIndex);
+      if (tail.trim().isNotEmpty) {
+        children.add(buildMarkdown(tail));
+      }
+
+      result = Column(
+        crossAxisAlignment: CrossAxisAlignment.stretch,
+        children: children,
       );
     }
 
-    final children = <Widget>[];
-    var currentIndex = 0;
-    for (final block in specialBlocks) {
-      // Skip overlapping blocks
-      if (block.start < currentIndex) continue;
-
-      final before = normalized.substring(currentIndex, block.start);
-      if (before.trim().isNotEmpty) {
-        children.add(buildMarkdown(before));
-      }
-
-      switch (block.type) {
-        case _BlockType.mermaid:
-          children.add(
-            ConduitMarkdown.buildMermaidBlock(context, block.content),
-          );
-        case _BlockType.chartJs:
-          children.add(
-            ConduitMarkdown.buildChartJsBlock(context, block.content),
-          );
-      }
-
-      currentIndex = block.end;
+    // Only wrap in SelectionArea when not streaming to avoid concurrent
+    // modification errors in Flutter's selection system during rapid updates
+    if (isStreaming) {
+      return result;
     }
 
-    final tail = normalized.substring(currentIndex);
-    if (tail.trim().isNotEmpty) {
-      children.add(buildMarkdown(tail));
-    }
-
-    return SelectionArea(
-      child: Theme(
-        data: Theme.of(context).copyWith(
-          textSelectionTheme: TextSelectionThemeData(
-            cursorColor: context.conduitTheme.buttonPrimary,
-          ),
-        ),
-        child: Column(
-          crossAxisAlignment: CrossAxisAlignment.stretch,
-          children: children,
-        ),
-      ),
-    );
+    return SelectionArea(child: result);
   }
 }
 

pubspec.lock

@@ -539,14 +539,6 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  flutter_markdown_plus:
-    dependency: "direct main"
-    description:
-      name: flutter_markdown_plus
-      sha256: "7f349c075157816da399216a4127096108fd08e1ac931e34e72899281db4113c"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.0.5"
   flutter_math_fork:
     dependency: "direct main"
     description:
@@ -701,6 +693,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "17.0.0"
+  gpt_markdown:
+    dependency: "direct main"
+    description:
+      name: gpt_markdown
+      sha256: "8174983f2ed7d8576d25810913e3afe3f8ffdaa3172c0c823b7cfc289b67f380"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.4"
   graphs:
     dependency: transitive
     description:

pubspec.yaml

@@ -31,12 +31,12 @@ dependencies:
   
   # UI Components - Markdown Rendering
   cached_network_image: ^3.3.1
-  flutter_markdown_plus: ^1.0.5
+  gpt_markdown: ^1.1.4
+  flutter_math_fork: ^0.7.2
   markdown: ^7.3.0
   webview_flutter: ^4.7.0
   socket_io_client: ^3.1.2
   yaml: ^3.1.2
-  flutter_math_fork: ^0.7.4