New Design System + Codebase Refresh (#1823)

Since the very first 0.1.0-alpha.1 release, we've been moving quickly to add new features to the Maybe app. In doing so, some parts of the codebase have become outdated, unnecessary, or overly-complex as a natural result of this feature prioritization.

Now that "core" Maybe is complete, we're moving into a second phase of development where we'll be working hard to improve the accuracy of existing features and build additional features on top of "core". This PR is a quick overhaul of the existing codebase aimed to:

- Establish the brand new and simplified dashboard view (pictured above)
- Establish and move towards the conventions introduced in Cursor rules and project design overview #1788
- Consolidate layouts and improve the performance of layout queries
- Organize the core models of the Maybe domain (i.e. Account::Entry, Account::Transaction, etc.) and break out specific traits of each model into dedicated concerns for better readability
- Remove stale / dead code from codebase
- Remove overly complex code paths in favor of simpler ones

app/views/shared/_drawer.html.erb

@@ -1,7 +1,7 @@
 <%# locals: (content:, reload_on_close: false) %>
 
 <%= turbo_frame_tag "drawer" do %>
-  <dialog class="ml-auto bg-white border border-alpha-black-25 rounded-2xl max-w-[480px] w-full shadow-xs h-full mt-4 mr-4 focus-visible:outline-hidden"
+  <dialog class="ml-auto bg-white shadow-border-xs rounded-2xl max-w-[480px] h-full w-full mt-4 mr-4 focus-visible:outline-hidden"
     data-controller="modal"
     data-action="click->modal#clickOutside"
     data-modal-reload-on-close-value="<%= reload_on_close %>">