feat: Support optional balance date column in account CSV imports (#736)

* Initial plan

* Add ability to specify balance date in AccountImport CSV

Co-authored-by: jjmata <187772+jjmata@users.noreply.github.com>

* Restore original Ruby version

* Fix linting issues - remove trailing whitespace

Co-authored-by: jjmata <187772+jjmata@users.noreply.github.com>

* Add error handling for date parsing in AccountImport

Co-authored-by: jjmata <187772+jjmata@users.noreply.github.com>

* Revert unintended Gemfile.lock changes

Co-authored-by: jjmata <187772+jjmata@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jjmata <187772+jjmata@users.noreply.github.com>

test/models/account_import_test.rb

@@ -63,8 +63,95 @@ class AccountImportTest < ActiveSupport::TestCase
     end
   end
 
-  test "column_keys returns expected keys" do
-    assert_equal %i[entity_type name amount currency], @import.column_keys
+  test "import creates accounts with explicit balance dates" do
+    import_csv = <<~CSV
+      type,name,amount,currency,date
+      depository,Main Checking,1000.00,USD,01/15/2024
+      depository,Savings Account,5000.00,USD,02/01/2024
+    CSV
+
+    @import.update!(
+      raw_file_str: import_csv,
+      entity_type_col_label: "type",
+      name_col_label: "name",
+      amount_col_label: "amount",
+      currency_col_label: "currency",
+      date_col_label: "date",
+      date_format: "%m/%d/%Y"
+    )
+
+    @import.generate_rows_from_csv
+
+    # Create mappings for account types
+    @import.mappings.create! key: "depository", value: "Depository", type: "Import::AccountTypeMapping"
+
+    @import.reload
+
+    # Perform the import
+    @import.publish
+
+    # Check if import succeeded
+    if @import.failed?
+      fail "Import failed with error: #{@import.error}"
+    end
+
+    assert_equal "complete", @import.status
+
+    # Verify accounts were created with correct dates
+    accounts = @import.accounts.order(:name)
+
+    checking_account = accounts.find { |a| a.name == "Main Checking" }
+    savings_account = accounts.find { |a| a.name == "Savings Account" }
+
+    checking_valuation = checking_account.valuations.opening_anchor.first
+    savings_valuation = savings_account.valuations.opening_anchor.first
+
+    assert_equal Date.parse("2024-01-15"), checking_valuation.entry.date
+    assert_equal Date.parse("2024-02-01"), savings_valuation.entry.date
+  end
+
+  test "import creates accounts with default dates when date column not provided" do
+    import_csv = <<~CSV
+      type,name,amount,currency
+      depository,Main Checking,1000.00,USD
+    CSV
+
+    @import.update!(
+      raw_file_str: import_csv,
+      entity_type_col_label: "type",
+      name_col_label: "name",
+      amount_col_label: "amount",
+      currency_col_label: "currency"
+    )
+
+    @import.generate_rows_from_csv
+
+    # Create mappings for account types
+    @import.mappings.create! key: "depository", value: "Depository", type: "Import::AccountTypeMapping"
+
+    @import.reload
+
+    # Perform the import
+    @import.publish
+
+    # Check if import succeeded
+    if @import.failed?
+      fail "Import failed with error: #{@import.error}"
+    end
+
+    assert_equal "complete", @import.status
+
+    # Verify account was created with default date (2 years ago or 1 day before oldest entry)
+    account = @import.accounts.first
+    valuation = account.valuations.opening_anchor.first
+
+    # Default date should be 2 years ago when there are no other entries
+    expected_default_date = 2.years.ago.to_date
+    assert_equal expected_default_date, valuation.entry.date
+  end
+
+  test "column_keys returns expected keys including date" do
+    assert_equal %i[entity_type name amount currency date], @import.column_keys
   end
 
   test "required_column_keys returns expected keys" do