feat: add tags and view todo widgets

[surgiie]

This PR:

• Removes "title" from todos in favor of a new "tags" field.
• Shows tags below todo description.
• FIxes issue where long todo text cuts off and pushes anything below out of view by truncating text.
• Add a "i" keymap that opens new "TodoDetailWidget" to allow viewing full text now that full description is truncated.
• Updates search filtering to use tags instead of title.
• Various other minor refactors and cleanup.