Add logical root change handling to SelectionPlugin

[BryanValverdeU]

Sometimes the onBlur and onFocus is not triggered from different logical roots.
To fix, when a logical root changes, re-attach the handlers to the new logical root so we can cache the selection in the onBlur event and re-create the selection on focus.

[Copilot]

Pull Request Overview

Adds support for re-attaching selection-related event handlers whenever the logical root changes, ensuring proper cleanup and re-initialization.

• Introduces a logicalRootDisposer field and extends dispose() to clean it up.
• Handles the logicalRootChanged event by re-attaching focus, blur (non-Safari), and drop handlers.
• Adds unit tests for non-Safari, Safari, and repeated logical root change scenarios.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/roosterjs-content-model-core/test/corePlugin/selection/SelectionPluginTest.ts	Added tests covering logicalRootChanged handling.
packages/roosterjs-content-model-core/lib/corePlugin/selection/SelectionPlugin.ts	Implemented logicalRootChanged event handling.

Comments suppressed due to low confidence (2)

packages/roosterjs-content-model-core/test/corePlugin/selection/SelectionPluginTest.ts:3169

• DEFAULT_DARK_COLOR_SUFFIX_COLOR is not imported or defined in this test file, causing a ReferenceError. Consider importing the constant from its module or replacing it with a literal mock value.

getDarkColor: (color: string) => `${DEFAULT_DARK_COLOR_SUFFIX_COLOR}${color}`

packages/roosterjs-content-model-core/test/corePlugin/selection/SelectionPluginTest.ts:3209

• DEFAULT_DARK_COLOR_SUFFIX_COLOR is referenced here but not defined. Add the necessary import or use a mock string literal to avoid test failures.

getDarkColor: (color: string) => `${DEFAULT_DARK_COLOR_SUFFIX_COLOR}${color}`