fix(yaml-front-matter): update start method regex to match exact YAML front matter format

src/renderer/src/components/RichEditor/extensions/enhanced-horizontal-rule.ts

@@ -1,74 +0,0 @@
-import { mergeAttributes } from '@tiptap/core'
-import { HorizontalRule } from '@tiptap/extension-horizontal-rule'
-
-/**
- * Enhanced HorizontalRule extension that preserves leading spaces in markdown
- *
- * Standard Markdown allows 0-3 spaces before a horizontal rule (---, ***, ___)
- * This extension preserves that indentation when serializing back to markdown
- */
-export const EnhancedHorizontalRule = HorizontalRule.extend({
-  addAttributes() {
-    return {
-      ...this.parent?.(),
-      // Store the number of leading spaces (0-3)
-      indentation: {
-        default: 0,
-        parseHTML: (element) => {
-          const indent = element.getAttribute('data-indentation')
-          return indent ? parseInt(indent, 10) : 0
-        },
-        renderHTML: (attributes) => {
-          if (!attributes.indentation) return {}
-          return {
-            'data-indentation': attributes.indentation
-          }
-        }
-      }
-    }
-  },
-
-  parseHTML() {
-    return [
-      {
-        tag: 'hr',
-        getAttrs: (element) => {
-          if (typeof element === 'string') return {}
-
-          const htmlElement = element as HTMLElement
-          const indentAttr = htmlElement.getAttribute('data-indentation')
-
-          return {
-            indentation: indentAttr ? parseInt(indentAttr, 10) : 0
-          }
-        }
-      }
-    ]
-  },
-
-  renderHTML({ HTMLAttributes }) {
-    return ['hr', mergeAttributes(this.options.HTMLAttributes, HTMLAttributes)]
-  },
-
-  // Custom markdown parsing to capture leading spaces
-  parseMarkdown(token) {
-    // The token.raw contains the original markdown including leading spaces
-    // Match 0-3 leading spaces before ---, ***, or ___
-    const match = /^( {0,3})(?:---|___|\*\*\*)/.exec(token.raw || '')
-    const indentation = match ? match[1].length : 0
-
-    return {
-      type: this.name,
-      attrs: {
-        indentation
-      }
-    }
-  },
-
-  // Custom markdown serialization to restore leading spaces
-  renderMarkdown(node) {
-    const indentation = node.attrs?.indentation || 0
-    const spaces = ' '.repeat(Math.min(indentation, 3)) // Max 3 spaces per spec
-    return spaces + '---\n\n'
-  }
-})