US-2b.7implemented Edit an existing receipt label
As a user who made a mistake in a previously saved receipt label I want re-open the receipt in the TUI with all fields pre-filled from the existing JSON so that I can correct a single field without re-entering everything.
Acceptance Criteria
- Running `--edit-receipt` loads the existing receipt JSON and pre-fills all TUI fields.
- Only changed fields are updated in the saved JSON.
- The old receipt label is replaced (not duplicated).
No DAG diagram: TUI enhancement — edits an existing receipt label in-place; the data path is the same as the original labelling story.
Demo video coming soon