Add Soft Delete for Payment Orders

[DevMukhtarr]

Description

This PR introduces soft delete functionality to the PaymentOrder and LockPaymentOrder schemas using a reusable SoftDeleteMixin.

The Implementation includes

• Created a SoftDeleteMixin in schema/mixins.go following Ent's soft delete pattern.
• Added SoftDeleteMixin to both PaymentOrder and LockPaymentOrder schemas.
• Update PaymentOrder edge in SenderProfile to use entsql.Cascade
• Added SkipSoftDelete context utility function
• Created database migration for new deleted_at field
• Added soft delete functionality to LockPaymentOrder and PaymentOrder schemas

References

closes #401

Testing

Tests were not included per ticket instruction.

Checklist

• I have added documentation and tests for new/changed functionality in this PR
• All active GitHub checks for tests, formatting, and security are passing
• The correct base branch is being used, if not main

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