Add lightweight summary endpoint for task statistics

- Add GET /api/residences/summary/ endpoint
- Returns task statistics without full residence data
- Enables efficient refresh of home screen summary counts

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

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

internal/router/router.go

@@ -244,6 +244,7 @@ func setupResidenceRoutes(api *gin.RouterGroup, residenceHandler *handlers.Resid
 		residences.GET("/", residenceHandler.ListResidences)
 		residences.POST("/", residenceHandler.CreateResidence)
 		residences.GET("/my-residences/", residenceHandler.GetMyResidences)
+		residences.GET("/summary/", residenceHandler.GetSummary)
 		residences.POST("/join-with-code/", residenceHandler.JoinWithCode)
 
 		residences.GET("/:id/", residenceHandler.GetResidence)