* Fix constant fields being editable on UI
* fix redirect to checkout if invoice is settled (redirect to receipt instead)
* enhance: make mirror field type able to map values
* Introduce invoice amount adjustment fields for form
* Integrate invoice amount adjustment fields for form on pos
* Support mirror in editor
* Indicate when special field names are used
* polsih mirror view and name suggestions for fields
* clarify
* hide hidden field from ui
* Minor adjustmentts
* Improve mirror field editing
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Co-authored-by: Dennis Reimann <mail@dennisreimann.de>
