Clarify which annotations are being used

🎯 Goal / Objective

A clear and concise description of what this task aims to achieve. Why is this task important?

In our codebase, we are using the word "annotation" to refer to multiple types of annotations applied onto an image. Sometimes the word refers to a "colored region annotation," where a color highlight is overlaid onto a portion of the image, and sometimes it refers to "text labels," which are text overlaid over the image, often with lines pointing from the text to a portion of the image.

There are places in the codebase where "annotation" is being used without clarifying which kind of annotation is being referred to, particularly in annotationOverlay.js. It should be clarified what annotations are being created or manipulated.

✅ Tasks to be Completed

A checklist of the specific, actionable steps required to complete this issue. This helps track progress.

• Add or reword existing comments or documentation in relevant files to clarify intent.
• If it seems necessary and helpful, rename symbols to clarify intent.

Acceptance Criteria

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• The new feature is implemented as described.
• All related code passes the repository's workflow checks (linting, tests).
• The application runs without errors after the changes are made.
• (If applicable) New automated tests have been added to cover the changes.
• Any related documentation has been updated, including JSDoc comments or docstrings

Additional Context

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Here is an example of an image with both a colored region annotation and a text label annotation (with a pointer line) applied on top:

Start by reading annotationOverlay.js and trace where image annotations are created or manipulated. Distinguish colored region annotations from text labels and update the relevant comments, JSDoc, or symbols so their intent is explicit. Done means the terminology is clear throughout the relevant code and the repository workflow checks pass.