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

db/migrate/20250710225721_add_valuation_kind.rb

@@ -0,0 +1,5 @@
+class AddValuationKind < ActiveRecord::Migration[7.2]
+  def change
+    add_column :valuations, :kind, :string, default: "reconciliation", null: false
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2025_07_02_173231) do
+ActiveRecord::Schema[7.2].define(version: 2025_07_10_225721) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
@@ -779,6 +779,7 @@ ActiveRecord::Schema[7.2].define(version: 2025_07_02_173231) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.jsonb "locked_attributes", default: {}
+    t.string "kind", default: "reconciliation", null: false
   end
 
   create_table "vehicles", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|