Add configurable path for job result messages separate from workers directory

[Copilot]

Job result messages were hardcoded to {WorkerPath}/__messages__/, coupling message storage to the workers directory.

Changes

• Configuration: Added JobResultMessagesPath setting to decouple message storage location
• API: Updated IJobManager methods to accept jobResultMessagesPath instead of deriving from workerPath
• Migration: Enhanced MigrateDetailedMessages with fallback to {WorkerPath}/__messages__ for backward compatibility

Usage

{
  "WorkerPath": "C:/temp/workers",
  "JobResultMessagesPath": "C:/temp/job-messages"
}

Messages now write directly to JobResultMessagesPath instead of a subdirectory under workers.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Separate configured location for job result messages instead of putting it within the workers directory</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Separate configured location for job result messages instead of putting it within the workers directory #44

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