🎨 优化扩展模块，完成ai接入和对话功能

data/st-core-scripts/scripts/showdown-underscore.js

@@ -0,0 +1,37 @@
+// Showdown extension that replaces words surrounded by singular underscores with <em> tags
+export const markdownUnderscoreExt = () => {
+    try {
+        if (!canUseNegativeLookbehind()) {
+            console.log('Showdown-underscore extension: Negative lookbehind not supported. Skipping.');
+            return [];
+        }
+
+        return [{
+            type: 'output',
+            regex: new RegExp('(<code(?:\\s+[^>]*)?>[\\s\\S]*?<\\/code>|<style(?:\\s+[^>]*)?>[\\s\\S]*?<\\/style>)|\\b(?<!_)_(?!_)(.*?)(?<!_)_(?!_)\\b', 'gi'),
+            replace: function(match, tagContent, italicContent) {
+                if (tagContent) {
+                    // If it's inside <code> or <style> tags, return unchanged
+                    return match;
+                } else if (italicContent) {
+                    // If it's an italic group, apply the replacement
+                    return '<em>' + italicContent + '</em>';
+                }
+                // If none of the conditions are met, return the original match
+                return match;
+            },
+        }];
+    } catch (e) {
+        console.error('Error in Showdown-underscore extension:', e);
+        return [];
+    }
+};
+
+function canUseNegativeLookbehind() {
+    try {
+        new RegExp('(?<!_)');
+        return true;
+    } catch (e) {
+        return false;
+    }
+}