Add a todo as a personal snippet
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We should be able to add a todo on a personal snippet (or a project snippet).
Once we can do that, we can also create a nice UI for adding a 'free-floating' todo task: we could have an 'Add todo' button on the todos page, that would ask for a single line of input, and create that as the title of a private personal snippet, with a todo already created. Then if you want to add more detail, comment on your progress to yourself, etc., you can!
/cc @DylanGriffith @victorwu
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