Feature: Add job serialization and payload normalization

Issue 4: Add Job Serialization & Payload Normalization

Title: Add job serialization and payload normalization

Description: Jobs need to be safely serialized before entering the queue and rehydrated when processed.

This issue ensures jobs behave consistently across drivers.

Goals:

• Serialize job data safely
• Support primitive + object payloads
• Normalize payload structure across drivers
• Avoid leaking framework internals into queue payloads

Acceptance Criteria:

• Jobs serialize/deserialize cleanly
• Payload format is documented
• Driver-independent payload structure