Media: optionally repair invalid imported metadata

[jzhvymetal]

Summary

• add a disabled-by-default repair for corroborated invalid metadata
• restrict it to completed, imported, local, single-segment video
• exclude recordings, live streams, discs, remote inputs, pictures, music, growing files, and valid rows
• include focused regression tests

Validation

• Focused Java tests passed in the Vibe extraction workspace.

Review state

Draft: a physical malformed-import corpus must prove recovery without changing valid media before merge.

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This replaces OpenSageTV#8, which was opened against an intermediate fork instead of the canonical SageTV repository. The topic was replayed without patch changes onto the current canonical master.

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[jzhvymetal]

Closing because the motivating invalid metadata row exists only on the modified Vibe test server, while the same valid MKV files report correct duration and seek normally through unmodified stock SageTV. The opt-in repair has not passed its physical malformed-import gate, and no stock-server user problem currently justifies adding playback-time database repair to Core.