# 999 - Fix seeding: tenants.external_id not-null

## Problem
Running `php artisan migrate:fresh --seed` fails with:

- `SQLSTATE[23502]: Not null violation: null value in column "external_id" of relation "tenants"`

The failing insert is from `Database\Seeders\PoliciesSeeder` creating a default tenant without populating `external_id`.

## Goal
- `migrate:fresh --seed` succeeds on a clean database.

## Non-goals
- No changes to production data or existing tenant records.

## Acceptance Criteria
- Seeding succeeds with PostgreSQL.
- A default tenant is created with a valid `external_id`.
- Tests covering the seeding path (minimal) pass.
