v2.32 — Collage Image Scale

Each collage image can now be scaled independently inside its panel.

• Scale slider and numeric entry from 10% to 300%, with a reset to 100%.
• Works with automatic grids and free layouts, preserving image proportions.
• Preview updates immediately and exports use the same scale.
• Exposed space uses the selected gap colour; crop positioning remains adjustable.
• README updated with the new controls.

Validated locally by the user in the application.