feat(LinkContext)!: Add activeState property

[webJose]

This alleviates the fact that the <Link> component lost the ability to set aria-current=page by default.

Now the <LinkContext> component can be used to specify CSS classes, CSS styles or aria attributes, meaning that creating navbars is now easier.

The unit testing for this component was very badly done, so it got re-worked, and revealed serious problems with the logic. All this has been corrected and is now covered by unit testing.

[Copilot]

Pull Request Overview

This PR adds support for the activeState property to the LinkContext component, allowing links within the context to automatically apply CSS classes, styles, or aria attributes when they become active. This feature complements the existing Link component's active state functionality and makes creating navigation components easier.

Key changes:

• Added activeState property to LinkContext with CSS classes, styles, and aria attributes
• Refactored Link component to separate activeFor and activeState properties
• Completely rewrote LinkContext tests with better test utilities and coverage

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/lib/LinkContext/LinkContext.svelte	Added activeState property support with proper inheritance and reactivity
src/lib/Link/Link.svelte	Split activeState into activeFor and activeState, added context integration
src/lib/types.ts	Removed key property from ActiveState type
src/testing/*.svelte	Added new test utilities and removed old test components
src/lib/LinkContext/LinkContext.svelte.test.ts	Complete rewrite with better test coverage
src/lib/Link/Link.svelte.test.ts	Added LinkContext integration tests
src/testing/test-utils.ts	Minor fix for library location mocking

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