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 In doing so, some parts of the codebase have become outdated, unnecessary, or overly-complex as a natural result of this feature prioritization.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/accounts/_account_sidebar_tabs.html.erb

@@ -0,0 +1,68 @@
+<%# locals: (family:) %>
+
+<div
+  class="space-y-3"
+  data-controller="tabs"
+  data-tabs-local-storage-key-value="account-sidebar-tabs"
+  data-tabs-active-class="bg-white shadow-sm text-primary"
+  data-tabs-inactive-class="text-secondary"
+  data-tabs-default-tab-value="assets-tab">
+  <div class="bg-surface-inset rounded-lg p-1 flex">
+    <button type="button" data-id="assets-tab" class="w-1/3 px-2 py-1 rounded-md text-sm text-secondary" data-tabs-target="btn" data-action="click->tabs#select">
+      Assets
+    </button>
+
+    <button type="button" data-id="debts-tab" class="w-1/3 px-2 py-1 rounded-md text-secondary text-sm" data-tabs-target="btn" data-action="click->tabs#select">
+      Debts
+    </button>
+
+    <button type="button" data-id="all-tab" class="w-1/3 px-2 py-1 rounded-md text-secondary text-sm" data-tabs-target="btn" data-action="click->tabs#select">
+      All
+    </button>
+  </div>
+
+  <div data-tabs-target="tab" id="assets-tab">
+    <%= link_to new_account_path(step: "method_select"),
+              class: "flex items-center gap-3 btn btn--ghost text-secondary mb-1",
+              data: { turbo_frame: "modal" } do %>
+      <%= icon("plus") %>
+      <span>New asset</span>
+    <% end %>
+
+    <div class="space-y-2">
+      <% family.balance_sheet.account_groups("asset").each do |group| %>
+        <%= render "accounts/accountable_group", account_group: group %>
+      <% end %>
+    </div>
+  </div>
+
+  <div data-tabs-target="tab" id="debts-tab" class="hidden">
+    <%= link_to new_account_path(step: "method_select"),
+              class: "flex items-center gap-3 btn btn--ghost text-secondary mb-1",
+              data: { turbo_frame: "modal" } do %>
+      <%= icon("plus") %>
+      <span>New debt</span>
+    <% end %>
+
+    <div class="space-y-2">
+      <% family.balance_sheet.account_groups("liability").each do |group| %>
+        <%= render "accounts/accountable_group", account_group: group %>
+      <% end %>
+    </div>
+  </div>
+
+  <div data-tabs-target="tab" id="all-tab" class="hidden">
+    <%= link_to new_account_path(step: "method_select"),
+              class: "flex items-center gap-3 btn btn--ghost text-secondary mb-1",
+              data: { turbo_frame: "modal" } do %>
+      <%= icon("plus") %>
+      <span>New account</span>
+    <% end %>
+
+    <div class="space-y-2">
+      <% family.balance_sheet.account_groups.each do |group| %>
+        <%= render "accounts/accountable_group", account_group: group %>
+      <% end %>
+    </div>
+  </div>
+</div>