feat: add minimalBranding option for cms

[stevenle]

Motivation

• Provide a config toggle to remove the Root CMS logo from the header and show the project/site name in its place for a minimal branded CMS UI.

Description

• Added a new optional minimalBranding?: boolean field to CMSPluginOptions in packages/root-cms/core/plugin.ts to expose the feature.
• Passed minimalBranding into the serialized client context at window.__ROOT_CTX.rootConfig with a default of false in packages/root-cms/core/app.tsx.
• Updated the UI global typing to include minimalBranding in packages/root-cms/ui/ui.tsx.
• Updated Layout.Top in packages/root-cms/ui/layout/Layout.tsx to conditionally hide the RootCMSLogo and version when minimalBranding is true and to render the project name right-aligned, and added a CSS modifier in packages/root-cms/ui/layout/Layout.css to handle positioning.

Testing

• Ran pnpm exec prettier --check on the changed files, which failed due to the environment attempting to download pnpm (network/proxy restriction) so formatting checks could not complete.
• Attempted a Playwright script to capture a screenshot at http://127.0.0.1:3000/cms, which failed because no local dev server was running at that address.
• No additional automated tests were run in this environment due to the above constraints.

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Codex Task