The manager can upload the day's PMS exports on production #74

Problem

The upload screen and the upload API are built separately. Nothing checks that the manager's real daily exports go through end to end.

Goal

On production, the manager uploads the day's PMS CSV exports, sees errors per file, follows the job until it finishes, and the new data is used by the next recommendations.

Scope

• Connect the upload screen to the upload API and job status.
• Try it with a real day's exports from the hotel.

Considerations

• Real exports often differ from the samples (encoding, date formats, extra columns). Expect to fix parser gaps here.

Acceptance criteria

• Uploading a real day's files on production succeeds and shows which nights were updated.
• A bad file shows an error that says how to fix it, and nothing from that upload is saved.
• Uploading the same files twice doesn't duplicate data.