Request: Add additional images to screenshot

[mstublefield]

Finally used the screenshot tool. Worked well! I still had to move over to SnagIt so I could combine it with other screenshots.

I love the layer panel and would love to be able to drag and drop additional images into cap so I can layer screenshots into a single image.

[linear]

CAP-631

[tembo]

Thanks for the feature request. Here's some relevant context from the codebase that could help with implementation:

Current Architecture

The screenshot editor's layer system lives in apps/desktop/src/routes/screenshot-editor/. The layers panel (LayersPanel.tsx) already supports drag-and-drop reordering of annotations and was added in PR #1432.

Current annotation types defined in the Rust backend are: arrow, circle, rectangle, text, and mask. Adding image layers would require:

1. Adding a new image variant to the AnnotationType enum (Rust side, which generates the TypeScript bindings)
2. Extending the Annotation struct with an optional image_path field
3. Adding image rendering in AnnotationLayer.tsx
4. Implementing drag-and-drop file handling on the preview canvas

Existing Patterns

There's already image import logic in BackgroundSettingsPopover.tsx (lines 389-413) that handles file selection and storage to the app data directory. This pattern could be adapted for image annotations.

The annotation system in context.tsx already tracks position, dimensions, rotation, and opacity for each layer, which would apply naturally to imported images.