feat(api): add import preflight validation

app/controllers/api/v1/imports_controller.rb

@@ -4,7 +4,7 @@ class Api::V1::ImportsController < Api::V1::BaseController
   include Pagy::Backend
 
   # Ensure proper scope authorization
-  before_action :ensure_read_scope, only: [ :index, :show ]
+  before_action :ensure_read_scope, only: [ :index, :show, :preflight ]
   before_action :ensure_write_scope, only: [ :create ]
   before_action :set_import, only: [ :show ]
 
@@ -119,6 +119,30 @@ def create
     render json: { error: "internal_server_error", message: e.message }, status: :internal_server_error
   end
 
+  def preflight
+    response = Import::Preflight.new(family: current_resource_owner.family, params: preflight_params).call
+    render json: response.payload, status: response.status
+  rescue ActiveRecord::RecordNotFound
+    render json: {
+      error: "record_not_found",
+      message: "The requested resource was not found"
+    }, status: :not_found
+  rescue CSV::MalformedCSVError => e
+    render json: {
+      error: "invalid_csv",
+      message: "CSV content could not be parsed",
+      errors: [ e.message ]
+    }, status: :unprocessable_entity
+  rescue StandardError => e
+    Rails.logger.error "ImportsController#preflight error: #{e.message}"
+    e.backtrace&.each { |line| Rails.logger.error line }
+
+    render json: {
+      error: "internal_server_error",
+      message: "An unexpected error occurred"
+    }, status: :internal_server_error
+  end
+
   private
 
     def set_import
@@ -155,10 +179,15 @@ def import_config_params
         :signage_convention,
         :col_sep,
         :amount_type_strategy,
-        :amount_type_inflow_value
+        :amount_type_inflow_value,
+        :rows_to_skip
       )
     end
 
+    def preflight_params
+      params.permit(*Import::Preflight::PARAM_KEYS)
+    end
+
     def create_sure_import(family)
       content, filename, content_type = sure_import_upload_attributes
       return unless content