feat: enhance feed detail functionality with MCP interface improvements (#45)

* feat: add feed detail page functionality with gin and MCP interfaces

Add comprehensive Feed detail page support:
- Create new FeedDetailAction in xiaohongshu/feed_detail.go
- Add HTTP API endpoint POST /api/v1/feeds/detail
- Add MCP tool 'get_feed_detail' for MCP protocol support
- Support feed_id and xsec_token parameters (both required)
- Raw __INITIAL_STATE__ JSON data saved to feed_detail.json
- Return structured data for both HTTP and MCP interfaces

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* feat: enhance feed detail functionality with MCP interface improvements

- Add comprehensive feed detail page support with proper data extraction
- Create dedicated feed_detail.go file for FeedDetailAction
- Optimize Go struct definitions based on actual JSON data analysis
- Remove unnecessary fields from FeedDetail, DetailImageInfo, CommentList, and Comment structs
- Update MCP interface description to reflect comment retrieval capability
- Support both HTTP REST API and MCP protocol interfaces
- Implement proper Vue 3 reactive data extraction from window.__INITIAL_STATE__
- Include feed content, user info, interaction data, and comment lists

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: restore JSON file writing for testing and improve code structure

- Restore feed_detail.json file writing for testing purposes
- Improve error handling by separating marshal and unmarshal steps
- Keep the original data extraction logic for complex Vue reactive data structure

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: simplify JSON unmarshaling using struct instead of map[string]any

- Replace complex map[string]any extraction with direct struct unmarshaling
- Define inline struct matching the actual JSON response structure
- Remove unnecessary extractFeedDetailData and extractNestedValue methods
- Significantly reduce code complexity and improve readability

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* docs: improve MCP interface descriptions for better usability

- Enhance get_feed_detail parameter descriptions with clear source information
- Clarify publish_content images parameter supports both local paths and URLs
- Improve search_feeds description to specify supported search types
- Keep descriptions concise and practical without over-complication

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: revert search_feeds keyword description to keep it simple

- Remove unnecessary details from keyword description
- Keep interface descriptions concise and clear

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

xiaohongshu/types.go

@@ -83,3 +83,56 @@ type Video struct {
 type VideoCapability struct {
 	Duration int `json:"duration"` // 视频时长，单位秒
 }
+
+// ================ Feed 详情页相关结构体 ================
+
+// FeedDetailResponse 表示 Feed 详情页完整响应
+type FeedDetailResponse struct {
+	Note     FeedDetail  `json:"note"`
+	Comments CommentList `json:"comments"`
+}
+
+// FeedDetail 表示详情页的笔记内容
+type FeedDetail struct {
+	NoteID       string            `json:"noteId"`
+	XsecToken    string            `json:"xsecToken"`
+	Title        string            `json:"title"`
+	Desc         string            `json:"desc"`
+	Type         string            `json:"type"`
+	Time         int64             `json:"time"`
+	IPLocation   string            `json:"ipLocation"`
+	User         User              `json:"user"`
+	InteractInfo InteractInfo      `json:"interactInfo"`
+	ImageList    []DetailImageInfo `json:"imageList"`
+}
+
+// DetailImageInfo 表示详情页的图片信息
+type DetailImageInfo struct {
+	Width      int    `json:"width"`
+	Height     int    `json:"height"`
+	URLDefault string `json:"urlDefault"`
+	URLPre     string `json:"urlPre"`
+	LivePhoto  bool   `json:"livePhoto,omitempty"`
+}
+
+// CommentList 表示评论列表
+type CommentList struct {
+	List    []Comment `json:"list"`
+	Cursor  string    `json:"cursor"`
+	HasMore bool      `json:"hasMore"`
+}
+
+// Comment 表示单条评论
+type Comment struct {
+	ID              string    `json:"id"`
+	NoteID          string    `json:"noteId"`
+	Content         string    `json:"content"`
+	LikeCount       string    `json:"likeCount"`
+	CreateTime      int64     `json:"createTime"`
+	IPLocation      string    `json:"ipLocation"`
+	Liked           bool      `json:"liked"`
+	UserInfo        User      `json:"userInfo"`
+	SubCommentCount string    `json:"subCommentCount"`
+	SubComments     []Comment `json:"subComments"`
+	ShowTags        []string  `json:"showTags"`
+}