Convert reused strings to consts

[davidjbradshaw]

No description provided.

[Copilot]

Pull Request Overview

This PR refactors the codebase to replace commonly used string literals with named constants to improve maintainability and reduce the risk of typos. The refactoring extracts event names, message types, and dimension strings into centralized constants defined in the common/consts.js file.

Key changes:

• Added 20+ new string constants to packages/common/consts.js for events, messages, and properties
• Updated packages/core/index.js to use the new constants instead of string literals throughout message handling, event listeners, and DOM operations
• Updated packages/child/index.js to use the new constants for consistency across the codebase

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
packages/common/consts.js	Defines new string constants for events, messages, and DOM properties
packages/core/index.js	Replaces string literals with imported constants for message types, events, and dimensions
packages/child/index.js	Replaces string literals with imported constants to maintain consistency

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