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 In doing so, some parts of the codebase have become outdated, unnecessary, or overly-complex as a natural result of this feature prioritization.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

config/locales/models/import/en.yml

@@ -1,13 +1,13 @@
 ---
 en:
   activerecord:
+    attributes:
+      import:
+        currency: Currency
+        number_format: Number Format
     errors:
       models:
         import:
           attributes:
             raw_file_str:
               invalid_csv_format: is not a valid CSV format
-    attributes:
-      import:
-        currency: Currency
-        number_format: Number Format

config/locales/models/trend/en.yml

@@ -3,7 +3,7 @@ en:
   activemodel:
     errors:
       models:
-        time_series/trend:
+        trend:
           attributes:
             current:
               must_be_of_the_same_type_as_previous: must be of the same type as previous