Always receive generated media in run output, regardless of storage settings

Images and audio generated during a run are now consistently included in run output regardless of the store_media setting. Media is scrubbed before being written to the database, keeping storage lean while ensuring callers always receive the full output they expect.

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Details:

Generated media (images, audio) is present in run output in all cases
Media is stripped from the payload prior to database storage, decoupling output completeness from persistence behavior
store_media continues to control persistence; output delivery is no longer tied to it