Backend: Add Request Correlation Propagation to Outbound Webhook and Email Calls

[devOnyx-01]

Description

This PR propagates request correlation identifiers to outbound webhook and email requests, improving end-to-end request traceability across external integrations.

Changes

• Propagated correlation IDs to outbound webhook requests.
• Propagated correlation IDs to outbound email requests.
• Ensured correlation identifiers are consistently forwarded across supported outbound integrations.
• Improved observability and debugging by enabling request tracing across service boundaries.

Why

Including correlation IDs in outbound requests makes it easier to trace the lifecycle of a request across internal services and third-party integrations, simplifying debugging, monitoring, and incident investigations.

Testing

• Verified correlation IDs are included in outbound webhook requests.
• Verified correlation IDs are included in outbound email requests.
• Confirmed existing webhook and email functionality remains unaffected.

Checklist

• Code follows project standards.
• Tested locally.
• No breaking changes introduced.
• Ready for review.

closes #629
closes #771
closes #773
closes #768

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