Coin values

Thanks for mostly restoring the coin values, but the values of the coins on the challenges and store are still not quite right. I remember the exact previous values and I'm happy to tell you what they were. There are many 50-coin challenges that are now worth 100, and also lots of the profile rings that previously cost 50 coins and now cost 100.
An additional point that I made before that I made before is that the coins of the todos should have some relation to the difficulty of the task. For example, an hour on Math Academy should make sense to give 100 coins, but a few minutes of scrolling through a discovery activity or watching a video should probably not be more than 20 coins.