Start and end balance anchors for historical account balances (#2455)

* Add kind field to valuation

* Fix schema conflict

* Add kind to valuation

* Scaffold opening balance manager

* Opening balance manager implementation

* Update account import to use opening balance manager + tests

* Update account to use opening balance manager

* Fix test assertions, usage of current balance manager

* Lint fixes

* Add Opening Balance manager, add tests to forward calculator

* Add credit card to "all cash" designation

* Simplify valuation model

* Add current balance manager with tests

* Add current balance logic to reverse calculator and plaid sync

* Tweaks to initial calc logic

* Ledger testing helper, tweak assertions for reverse calculator

* Update test assertions

* Extract balance transformer, simplify calculators

* Algo simplifications

* Final tweaks to calculators

* Cleanup

* Fix error, propagate sync errors up to parent

* Update migration script, valuation naming

app/models/valuation.rb

@@ -1,6 +1,12 @@
 class Valuation < ApplicationRecord
   include Entryable
 
+  enum :kind, {
+    reconciliation: "reconciliation",
+    opening_anchor: "opening_anchor",
+    current_anchor: "current_anchor"
+  }, validate: true, default: "reconciliation"
+
   class << self
     def build_reconciliation_name(accountable_type)
       Valuation::Name.new("reconciliation", accountable_type).to_s
@@ -14,10 +20,4 @@ class Valuation < ApplicationRecord
       Valuation::Name.new("current_anchor", accountable_type).to_s
     end
   end
-
-  # TODO: Remove this method when `kind` column is added to valuations table
-  # This is a temporary implementation until the database migration is complete
-  def kind
-    "reconciliation"
-  end
 end