Change way db file are stored

[Androz2091]

[Androz2091]

Resolved by the S3 migration. Encrypted package blobs are now stored in the dumpus-prod-package-data S3 bucket and served to clients via short-lived presigned URLs through /blob. Only the AES IV stays in Postgres on the saved_package_data row.

References:

• S3 bucket + lifecycle: infra/terraform/blob_storage.tf
• Worker upload path: src/blob_storage.py
• API /blob handler: src/app.py
• One-shot migration that drops the legacy encrypted_data column from Postgres: src/db.py:42-46