Take the Day planner out of beta #1182

The day planner feature was released last week in closed beta. This required users to opt-in to the beta feature by clicking the flask icon and then toggling the feature from a pop-up menu. That worked, but it's too high-friction to keep. Now that we've tested the day planner and are more confident in it not breaking, we can release into the regular app so that it's available by default.

• Add a note about how events are saved in the browser, so clearing your browser data will remove all the events. Encourage users to think about day tasks as simple ways to stay focused, rather than tasks that you'll track over long timelines and go back to for reference. Mention how we will store the tasks in our cloud DB for protection soon, but now is a good time to get familiar with the workflow and start taking control of your day.