Add --test mode for cut testing without wasting ink

[Alan-Cha]

Feature Request

Add a --test option to create_pdf.py that generates a minimal test template for testing cutting and registration without wasting ink.

Problem

Users need to test their cutting setup and registration marks before printing full card sets, but currently must use actual card images which wastes significant amounts of ink during calibration.

Proposed Solution

Add a --test flag that:

• Ignores all images in game/front, game/back, and game/double_sided
• Dynamically generates simple test cards consisting of:
  • A thin black border (rounded rectangle matching the card shape)
  • Minimal ink usage
• Maintains the same layout, registration marks, and page structure as normal output

Use Case

Users can run:

python create_pdf.py --test

This creates a PDF with the same number of cards per page, registration marks, and cutting guides as their actual print job would have, but with minimal ink test cards instead of actual artwork.

Benefits

• Test cutting accuracy and registration alignment
• Verify paper/card size settings are correct
• Practice cutting technique
• Significantly reduce ink/toner costs during setup and calibration

Alternative Names

If --test seems too generic, alternatives could be:

• --test-cut
• --calibration
• --dry-run
• --template-only

Technical Notes

Test cards should:

• Use the configured card size and paper size
• Include registration marks if specified
• Generate the same number of cards as would normally be created
• Have rounded corners matching the card shape
• Use a thin (e.g., 1-2pt) black stroke for the border