FSE: Add focus mode and top toolbar modes

[noahtallen]

Description

Adds top toolbar feature toggle to the site editor. Mostly copied from edit-post. (related: #22535)

While adding this, I noticed that there are a lot of small margin & style differences between edit-site and edit-post. For example, the inserter button isn't a proper square. Additionally, we are missing most of the mobile styles already coded in edit-post. I think we need to share more code between the two since the requirements for both toolbars are nearly identical. Should that kind of refactor go into the interface package?

How has this been tested?

Locally in edit site

Screenshots

Types of changes

new feature

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.

[github-actions]

Size Change: +491 B (0%)

Total Size: 1.12 MB

Filename	Size	Change
build/edit-site/index.js	13.2 kB	+257 B (1%)
build/edit-site/style-rtl.css	5.45 kB	+116 B (2%)
build/edit-site/style.css	5.45 kB	+118 B (2%)

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.02 kB	0 B
build/annotations/index.js	3.62 kB	0 B
build/api-fetch/index.js	3.39 kB	0 B
build/autop/index.js	2.83 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/index.js	6.93 kB	0 B
build/block-directory/style-rtl.css	790 B	0 B
build/block-directory/style.css	791 B	0 B
build/block-editor/index.js	105 kB	0 B
build/block-editor/style-rtl.css	10.9 kB	0 B
build/block-editor/style.css	10.9 kB	0 B
build/block-library/editor-rtl.css	7.17 kB	0 B
build/block-library/editor.css	7.17 kB	0 B
build/block-library/index.js	119 kB	0 B
build/block-library/style-rtl.css	7.48 kB	0 B
build/block-library/style.css	7.48 kB	0 B
build/block-library/theme-rtl.css	684 B	0 B
build/block-library/theme.css	686 B	0 B
build/block-serialization-default-parser/index.js	1.88 kB	0 B
build/block-serialization-spec-parser/index.js	3.1 kB	0 B
build/blocks/index.js	48.1 kB	0 B
build/components/index.js	190 kB	0 B
build/components/style-rtl.css	17.1 kB	0 B
build/components/style.css	17.1 kB	0 B
build/compose/index.js	9.24 kB	0 B
build/core-data/index.js	11.4 kB	0 B
build/data-controls/index.js	1.29 kB	0 B
build/data/index.js	8.42 kB	0 B
build/date/index.js	5.47 kB	0 B
build/deprecated/index.js	771 B	0 B
build/dom-ready/index.js	568 B	0 B
build/dom/index.js	3.11 kB	0 B
build/edit-navigation/index.js	6.63 kB	0 B
build/edit-navigation/style-rtl.css	857 B	0 B
build/edit-navigation/style.css	856 B	0 B
build/edit-post/index.js	302 kB	0 B
build/edit-post/style-rtl.css	12.2 kB	0 B
build/edit-post/style.css	12.2 kB	0 B
build/edit-widgets/index.js	7.73 kB	0 B
build/edit-widgets/style-rtl.css	4.59 kB	0 B
build/edit-widgets/style.css	4.59 kB	0 B
build/editor/editor-styles-rtl.css	425 B	0 B
build/editor/editor-styles.css	428 B	0 B
build/editor/index.js	44.6 kB	0 B
build/editor/style-rtl.css	5.06 kB	0 B
build/editor/style.css	5.06 kB	0 B
build/element/index.js	4.65 kB	0 B
build/escape-html/index.js	733 B	0 B
build/format-library/index.js	7.64 kB	0 B
build/format-library/style-rtl.css	502 B	0 B
build/format-library/style.css	502 B	0 B
build/hooks/index.js	2.13 kB	0 B
build/html-entities/index.js	622 B	0 B
build/i18n/index.js	3.56 kB	0 B
build/is-shallow-equal/index.js	711 B	0 B
build/keyboard-shortcuts/index.js	2.51 kB	0 B
build/keycodes/index.js	1.94 kB	0 B
build/list-reusable-blocks/index.js	3.13 kB	0 B
build/list-reusable-blocks/style-rtl.css	226 B	0 B
build/list-reusable-blocks/style.css	226 B	0 B
build/media-utils/index.js	5.29 kB	0 B
build/notices/index.js	1.79 kB	0 B
build/nux/index.js	3.4 kB	0 B
build/nux/style-rtl.css	616 B	0 B
build/nux/style.css	613 B	0 B
build/plugins/index.js	2.56 kB	0 B
build/primitives/index.js	1.5 kB	0 B
build/priority-queue/index.js	789 B	0 B
build/redux-routine/index.js	2.85 kB	0 B
build/rich-text/index.js	14.8 kB	0 B
build/server-side-render/index.js	2.68 kB	0 B
build/shortcode/index.js	1.7 kB	0 B
build/token-list/index.js	1.28 kB	0 B
build/url/index.js	4.02 kB	0 B
build/viewport/index.js	1.84 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.17 kB	0 B

_{compressed-size-action}

[epiqueras]

Should that kind of refactor go into the interface package?

Yes