Add annual reports for accounts (#28693)

app/lib/annual_report/source.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class AnnualReport::Source
+  attr_reader :account, :year
+
+  def initialize(account, year)
+    @account = account
+    @year = year
+  end
+
+  protected
+
+  def year_as_snowflake_range
+    (Mastodon::Snowflake.id_at(DateTime.new(year, 1, 1))..Mastodon::Snowflake.id_at(DateTime.new(year, 12, 31)))
+  end
+end