Setup BD SMS for H1 2025 (#5523)

**Story card:**
[sc-14511](https://app.shortcut.com/simpledotorg/story/14511/enable-sms-for-uhcs-in-bd)

## Because

We need to resume sending SMSs in BD

## This addresses

Generating a `data_migration` to setup SMSs in BD

## Test instructions

n/a

db/data/20250121130710_setup_bdh12025_sms_schedule.rb

@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+class SetupBdh12025SmsSchedule < ActiveRecord::Migration[6.1]
+  EXPERIMENTS_DATA = %w[Jan Feb Mar Apr May Jun].map do |month|
+    {
+      current_experiment_name: "Current patients #{month} 2025",
+      stale_experiment_name: "Stale patients #{month} 2025",
+      start_time: "#{month} 2025".to_datetime.beginning_of_month,
+      end_time: "#{month} 2025".to_datetime.end_of_month
+    }
+  end
+
+  MAX_PATIENTS_PER_DAY = 5000
+
+  INCLUDED_FACILITY_SLUG = Facility
+    .where(facility_type: "UHC")
+    .where.not(slug: [
+      "uhc-fatikchori",
+      "uhc-parsuram",
+      "uhc-daganbhuiya"
+    ])
+    .pluck(:slug)
+
+  REGION_FILTERS = {
+    "facilities" => {"include" => INCLUDED_FACILITY_SLUG}
+  }.freeze
+
+  def up
+    return unless CountryConfig.current_country?("Bangladesh") && SimpleServer.env.production?
+    EXPERIMENTS_DATA.each do |experiment_data|
+      ActiveRecord::Base.transaction do
+        Experimentation::Experiment.current_patients.create!(
+          name: (experiment_data[:current_experiment_name]).to_s,
+          start_time: experiment_data[:start_time],
+          end_time: experiment_data[:end_time],
+          max_patients_per_day: MAX_PATIENTS_PER_DAY,
+          filters: REGION_FILTERS
+        ).tap do |experiment|
+          treatment_group = experiment.treatment_groups.create!(description: "cascade_free")
+          treatment_group.reminder_templates.create!(message: "notifications.set03.free", remind_on_in_days: 1)
+          treatment_group.reminder_templates.create!(message: "notifications.set03.free", remind_on_in_days: 3)
+        end
+      end
+
+      ActiveRecord::Base.transaction do
+        Experimentation::Experiment.stale_patients.create!(
+          name: (experiment_data[:stale_experiment_name]).to_s,
+          start_time: experiment_data[:start_time],
+          end_time: experiment_data[:end_time],
+          max_patients_per_day: MAX_PATIENTS_PER_DAY,
+          filters: REGION_FILTERS
+        ).tap do |experiment|
+          treatment_group = experiment.treatment_groups.create!(description: "cascade_free")
+          treatment_group.reminder_templates.create!(message: "notifications.set02.free", remind_on_in_days: 0)
+          treatment_group.reminder_templates.create!(message: "notifications.set03.free", remind_on_in_days: 3)
+        end
+      end
+    end
+  end
+
+  def down
+    return unless CountryConfig.current_country?("Bangladesh") && SimpleServer.env.production?
+    EXPERIMENTS_DATA.each do |experiment_data|
+      Experimentation::Experiment.current_patients.find_by_name(experiment_data[:current_experiment_name])&.cancel
+      Experimentation::Experiment.stale_patients.find_by_name(experiment_data[:stale_experiment_name])&.cancel
+    end
+  end
+end