The HabitCreateDialog and ProjectCreateDialog were mounted with local
state but the topbar uses useCreateDialogStore, and the store had no
consumer on /habits or /projects. So topbar clicks did nothing, and the
page-level button may have been dead too due to a stale build.
Mount <CreateItemDialog> in both pages so:
- The topbar New habit / New project button opens the dialog
- The page-level buttons open the same dialog via the store
- A single CreateItemDialog handles task/project/habit creation
Bug #3 (New habit) + Bug #4 (New project) are fixed by this commit.