feat: add knowledge markdown formatting and detail retrieval

- Implemented KnowledgeWebsiteMarkdownPrompt for formatting webpage content into Markdown.
- Added GetItemDetail method in KnowledgeHandler to retrieve knowledge item details.
- Introduced KnowledgeDetailDrawer component for displaying knowledge item details in the admin web interface.
- Created MarkdownPreview component for rendering Markdown content.
- Added knowledge chunking and URL parsing logic to handle webpage content extraction and formatting.
- Updated database schema to include markdown_content in knowledge_items table.

apps/admin-web/package.json

@@ -21,6 +21,7 @@
     "@vueuse/core": "^14.2.1",
     "ant-design-vue": "^4.2.6",
     "dayjs": "^1.11.20",
+    "markdown-it": "^14.1.1",
     "pinia": "^3.0.4",
     "vue": "^3.5.31",
     "vue-i18n": "^10.0.5",
@@ -28,6 +29,7 @@
     "zod": "^4.3.6"
   },
   "devDependencies": {
+    "@types/markdown-it": "^14.1.2",
     "@types/node": "^24.0.0",
     "@vitejs/plugin-vue": "^6.0.5",
     "typescript": "^5.9.3",