Normalize default format

[JiuqingSong]

When set default format, we accept any kind of string value to font, color, ...

Some value will be modified by browser when assign to DOM, such as font. For example, when apply font font1,font2,font3, browser will change it to font1, font2, font3. So if we compare the applied font and default font, they will be different.

So we can do a normalization to the format before we use it, by applying it into a temp SPAN then retrieve it. Then we store the normalized default format in FormatPlugin and always apply this normalized one.

This can solve an issue that some IME got broken because we are applying default format which we don't need to.

[Copilot]

Pull Request Overview

This PR normalizes the default text format applied to the DOM, ensuring consistency between the intended format and the browser-modified version. Key changes include adding a new helper function "normalizeSegmentFormat" and its corresponding tests, exporting the normalization utility from the main package, and updating the FormatPlugin and its tests to use the normalized format.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/roosterjs-content-model-dom/test/modelApi/common/normalizeSegmentFormatTest.ts	Added tests covering various normalization cases for segment formats.
packages/roosterjs-content-model-dom/lib/modelApi/common/normalizeSegmentFormat.ts	Introduced normalization logic by rendering a temp span element.
packages/roosterjs-content-model-dom/lib/index.ts	Exported the newly added normalization function.
packages/roosterjs-content-model-core/test/corePlugin/format/FormatPluginTest.ts	Updated tests to use a mocked environment.
packages/roosterjs-content-model-core/lib/corePlugin/format/FormatPlugin.ts	Updated plugin initialization to normalize the default format.

Comments suppressed due to low confidence (1)

packages/roosterjs-content-model-dom/test/modelApi/common/normalizeSegmentFormatTest.ts:6

• Consider adding a test case for when the environment parameter is undefined to verify the fallback context creation in normalizeSegmentFormat.

describe('normalizeSegmentFormat', () => {