Admin CSV Import

What

• Add a CSV import option to allow bulk creations of the entities in a school

Context

• This CSV import would only be run when there aren't already existing entities in the school for this year; it does not need to handle merging with intitial data.
• The import should provide a template to download with the necessary columns
• The import should be able to create classrooms, teachers, students all at once

AC

• An admin can download a CSV template from the school's page with the required columns for classrooms, teachers, and students
• An admin can upload a completed CSV for a school to bulk-create its classrooms, teachers, and students in a single import
• The import option is only available when the school has no existing classrooms, teachers, or students — if the school already has data, the import is not offered
• Each classroom row includes at least one program/level so it satisfies the existing "at least one program enrolled" requirement
• Each student row requires first name, last name, and grade level (gender and email are optional), and associates the student with the classroom and school from their row
• If any row in the CSV fails validation (missing required field, unrecognized program, etc.), the entire import is rejected as a single transaction — no classrooms, teachers, or students are created — and the admin sees which row(s) and column(s) failed
• On a fully valid CSV, all classrooms, teachers, and students are created together, with students correctly linked to their classroom