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.

server/internal/shared/llm/client.go

@@ -13,6 +13,7 @@ import (
 var ErrNotConfigured = errors.New("llm provider is not configured")
 
 type GenerateRequest struct {
+	Model           string
 	Prompt          string
 	Timeout         time.Duration
 	MaxOutputTokens int64