Add custom markdown tokenizer with logging for YAML front matter

- Implement markdown tokenizer with start() and tokenize() methods for parsing YAML front matter
- Add comprehensive logging throughout tokenization, parsing, and serialization processes
- Improve markdown serialization to ensure proper --- delimiter handling

src/renderer/src/components/RichEditor/extensions/yaml-front-matter.ts

@@ -1,8 +1,11 @@
+import { loggerService } from '@logger'
 import { mergeAttributes, Node } from '@tiptap/core'
 import { ReactNodeViewRenderer } from '@tiptap/react'
 
 import YamlFrontMatterNodeView from '../components/YamlFrontMatterNodeView'
 
+const logger = loggerService.withContext('YamlFrontMatterExtension')
+
 declare module '@tiptap/core' {
   interface Commands<ReturnType> {
     yamlFrontMatter: {
@@ -17,8 +20,113 @@ export const YamlFrontMatter = Node.create({
   atom: true,
   draggable: false,
 
-  // Markdown token name for custom parsing
-  markdownTokenName: 'yamlFrontMatter',
+  // Custom tokenizer for YAML front matter
+  markdownTokenizer: {
+    name: 'yamlFrontMatter',
+    level: 'block',
+    // Optimization: check if content starts with ---
+    start(src: string) {
+      logger.info('🔍 Tokenizer start() called', {
+        srcLength: src.length,
+        srcPrefix: src.substring(0, 60).replace(/\n/g, '\\n'),
+        startsWithDashes: src.startsWith('---\n')
+      })
+
+      const result = src.match(/^---\n/) ? 0 : -1
+      logger.info('✅ Tokenizer start() result:', { result })
+      return result
+    },
+    // Parse YAML front matter
+    tokenize(src: string) {
+      logger.info('🔍 Tokenizer tokenize() called', {
+        srcLength: src.length,
+        srcPrefix: src.substring(0, 120).replace(/\n/g, '\\n')
+      })
+
+      // Match: ---\n...yaml content...\n---
+      const match = /^---\n([\s\S]*?)\n---(?:\n|$)/.exec(src)
+
+      if (!match) {
+        logger.warn('❌ Tokenizer tokenize() - NO MATCH FOUND')
+        return undefined
+      }
+
+      const token = {
+        type: 'yamlFrontMatter',
+        raw: match[0],
+        text: match[1] // YAML content without delimiters
+      }
+
+      logger.info('✅ Tokenizer tokenize() - MATCH FOUND', {
+        rawLength: token.raw.length,
+        textLength: token.text.length,
+        textPreview: token.text.substring(0, 100).replace(/\n/g, '\\n')
+      })
+
+      return token
+    }
+  },
+
+  // Parse markdown token to Tiptap JSON
+  parseMarkdown(token, helpers) {
+    logger.info('🔍 parseMarkdown() called', {
+      tokenType: token.type,
+      hasText: !!token.text,
+      textLength: token.text?.length || 0,
+      textPreview: token.text?.substring(0, 100).replace(/\n/g, '\\n'),
+      hasTokens: !!token.tokens,
+      tokensLength: token.tokens?.length || 0
+    })
+
+    const result = {
+      type: this.name,
+      attrs: {
+        content: token.text || ''
+      },
+      content: helpers.parseChildren(token.tokens || [])
+    }
+
+    logger.info('✅ parseMarkdown() result', {
+      type: result.type,
+      contentLength: result.attrs.content.length,
+      hasContent: !!result.content
+    })
+
+    return result
+  },
+
+  // Serialize Tiptap node to markdown
+  renderMarkdown(node) {
+    logger.info('🔍 renderMarkdown() called', {
+      nodeType: node.type,
+      hasContent: !!node.attrs?.content,
+      contentLength: node.attrs?.content?.length || 0,
+      contentPreview: node.attrs?.content?.substring(0, 100).replace(/\n/g, '\\n')
+    })
+
+    const content = node.attrs?.content || ''
+    if (!content.trim()) {
+      logger.info('⚠️ renderMarkdown() - empty content, returning empty string')
+      return ''
+    }
+
+    const trimmedContent = content.trim()
+    let result = ''
+
+    // Ensure proper format with closing ---
+    if (trimmedContent.endsWith('---')) {
+      result = trimmedContent + '\n\n'
+    } else {
+      result = trimmedContent + '\n---\n\n'
+    }
+
+    logger.info('✅ renderMarkdown() result', {
+      resultLength: result.length,
+      resultPreview: result.substring(0, 120).replace(/\n/g, '\\n')
+    })
+
+    return result
+  },
 
   addOptions() {
     return {
@@ -78,30 +186,6 @@ export const YamlFrontMatter = Node.create({
     ]
   },
 
-  // Parse markdown token to Tiptap JSON
-  parseMarkdown(token: any) {
-    // Extract YAML content from the token
-    // The content should be the raw YAML text between --- delimiters
-    const content = token.text || token.raw || ''
-    return {
-      type: this.name,
-      attrs: {
-        content: content.trim()
-      }
-    }
-  },
-
-  // Serialize Tiptap node to markdown
-  renderMarkdown(node: any) {
-    const content = node.attrs.content || ''
-    // If content doesn't end with ---, add it
-    const trimmedContent = content.trim()
-    if (trimmedContent && !trimmedContent.endsWith('---')) {
-      return trimmedContent + '\n---\n\n'
-    }
-    return trimmedContent ? trimmedContent + '\n\n' : ''
-  },
-
   addCommands() {
     return {
       insertYamlFrontMatter: