feat(testing): add idempotent test-database seeding script and integration tests (#394)

[tomasbogado203-bit]

Summary

Resolves #394 by adding an idempotent test-database seeding script (src/seeders/test.seeder.ts), npm scripts (
pm run seed:test,
pm run db:seed:test), production safety guards, and integration test coverage ( ests/integration/testSeeder.integration.test.ts).

Features

• Idempotent Test Seeder (src/seeders/test.seeder.ts):
  • Seeds representative users across all platform roles (�dmin@audioblocks.test, �rtist1@audioblocks.test, �rtist2@audioblocks.test, listener1@audioblocks.test, listener2@audioblocks.test).
  • Seeds genres (Pop, Hip-Hop, Electronic, Rock, Afrobeat, Jazz, R&B).
  • Seeds representative albums (Neon Horizons, Stellar Grooves Vol. 1).
  • Seeds representative songs linked to artists, genres, and albums.
  • Safe & idempotent: running multiple times updates/matches existing records without creating duplicates or failing unique constraints.
• Safety Guards:
  • �ssertTestEnvironmentSafety() blocks execution when NODE_ENV=production unless explicitly allowed via ALLOW_TEST_SEED=true.

• NPM Scripts:

pm run seed:test and
pm run db:seed:test.

• Integration Tests ( ests/integration/testSeeder.integration.test.ts):
  • Verifies safety guards against production mode.
  • Verifies seeded entity counts and relationships.
  • Verifies multi-execution idempotency.
• Documentation:
  • Updated README.md with script usage and descriptions.

Verification

px jest tests/integration/testSeeder.integration.test.ts --runInBand (5/5 tests passing)

• Lint and Prettier pre-commit hooks passed.