Suppress AWS SDK v1 deprecation warnings in lint

[Copilot]

The dependency update to aws-sdk-go v1.55.8 introduced deprecation warnings (SA1019) that fail linting. AWS SDK Go v1 is deprecated as of July 31, 2025, but migration to v2 is outside the scope of this dependency update.

Changes

• Added //nolint:staticcheck comments to AWS SDK v1 imports in S3 blob storage, SES email service, and blob storage tests
• Comments document that migration to AWS SDK v2 is planned for the future

import (
    "github.com/aws/aws-sdk-go/aws"                 //nolint:staticcheck // AWS SDK v1 will be migrated to v2 in the future
    "github.com/aws/aws-sdk-go/aws/session"         //nolint:staticcheck // AWS SDK v1 will be migrated to v2 in the future
)

This allows the dependency update to proceed while deferring the SDK migration to a separate effort.

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