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

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

---------

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

handlers_api.go

@@ -103,6 +103,27 @@ func (s *AppServer) searchFeedsHandler(c *gin.Context) {
 	respondSuccess(c, result, "搜索Feeds成功")
 }
 
+// getFeedDetailHandler 获取Feed详情
+func (s *AppServer) getFeedDetailHandler(c *gin.Context) {
+	var req FeedDetailRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		respondError(c, http.StatusBadRequest, "INVALID_REQUEST",
+			"请求参数错误", err.Error())
+		return
+	}
+
+	// 获取 Feed 详情
+	result, err := s.xiaohongshuService.GetFeedDetail(c.Request.Context(), req.FeedID, req.XsecToken)
+	if err != nil {
+		respondError(c, http.StatusInternalServerError, "GET_FEED_DETAIL_FAILED",
+			"获取Feed详情失败", err.Error())
+		return
+	}
+
+	c.Set("account", "ai-report")
+	respondSuccess(c, result, "获取Feed详情成功")
+}
+
 // healthHandler 健康检查
 func healthHandler(c *gin.Context) {
 	respondSuccess(c, map[string]any{