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 In doing so, some parts of the codebase have become outdated, unnecessary, or overly-complex as a natural result of this feature prioritization.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

@@ -1,33 +1,17 @@
 class Account::Transaction < ApplicationRecord
-  include Account::Entryable
+  include Account::Entryable, Transferable
 
   belongs_to :category, optional: true
   belongs_to :merchant, optional: true
+
   has_many :taggings, as: :taggable, dependent: :destroy
   has_many :tags, through: :taggings
 
-  has_one :transfer_as_inflow, class_name: "Transfer", foreign_key: "inflow_transaction_id", dependent: :destroy
-  has_one :transfer_as_outflow, class_name: "Transfer", foreign_key: "outflow_transaction_id", dependent: :destroy
-
-  # We keep track of rejected transfers to avoid auto-matching them again
-  has_one :rejected_transfer_as_inflow, class_name: "RejectedTransfer", foreign_key: "inflow_transaction_id", dependent: :destroy
-  has_one :rejected_transfer_as_outflow, class_name: "RejectedTransfer", foreign_key: "outflow_transaction_id", dependent: :destroy
-
   accepts_nested_attributes_for :taggings, allow_destroy: true
 
-  scope :active, -> { where(excluded: false) }
-
   class << self
     def search(params)
       Account::TransactionSearch.new(params).build_query(all)
     end
   end
-
-  def transfer
-    transfer_as_inflow || transfer_as_outflow
-  end
-
-  def transfer?
-    transfer.present?
-  end
 end