Basically, it looks for the oldest date you have for the column [created date], and builds a sequential date range until the time of refresh - so it always has calendar information for all data points in the set.
With both the numeric and text values, you can use "Sort by" to properly order them in visuals. If you want your week numbers to start on a Sunday instead of Monday, change the "1" to a "2" in ISOWeekofYear column - however ISO Standard is a Monday Start.
I'm still pretty new to PowerBI, but I'll help if I can! If you have suggestions or modifications, I'd love to hear them.
EDIT: I changed how the week number is calculated, so I can use ISO Week Numbers. This also helped fix the "week Ending column, which broke when spanning multiple years that included a leap year. Let me know if you find any problems!