New Field : File Upload Field

[lattln]

Summary
Introduce a new File Upload field type in E-Sheet to support HL7/FHIR-style form inputs where users can upload one or more files directly into a form.

User Story
As a form builder, I want to add a file upload question to a form so that end users can attach files during form completion.

Builder View Requirements
The file upload field should support configuration of:

• Question/label text
• Maximum file size
• Maximum number of files allowed
• Accepted file types
• Optional helper text or instructions, if supported by the existing field editor pattern

Preview / Runtime Behavior
In the form preview and live form:

• The field should render as a file upload control, such as a drop zone or clickable upload area
• Clicking the upload area should open the native file picker
• The control should inherit the builder settings for:
  • max file size
  • max file count
  • accepted file types
• Validation errors should be shown if a selected file exceeds size or type constraints

Acceptance Criteria

• A new File Upload field type can be added from the builder
• The field label/question is editable
• Builder settings exist for max file size, max file count, and accepted file types
• The preview renders a functional upload UI
• File picker restrictions and validation reflect builder settings
• Users can upload files according to the configured limits
• Unsupported file types or oversized files are rejected with clear feedback

Notes

• This field is intended to align E-Sheet more closely with FHIR/HL7 form capabilities
• If file storage handling is already defined elsewhere, this ticket should only cover form field creation and validation behavior