API Tokens and Header Controls

This update introduced practical product controls for both developers and operators.

What changed

• Added API token feature support with conditional rendering paths.
• Added hideBorderX configuration for more flexible header presentation.
• Simplified default layout header structure for a cleaner top-level navigation area.
• Updated tooling config to exclude skills directory from Biome and TypeScript checks.

Commits included

• d563264 feat: implement API tokens feature with conditional rendering
• 546c9a0 feat: add hideBorderX configuration option for header
• 90bec07 refactor: simplify header structure in default layout
• ddac416 chore: update biome and tsconfig to exclude skills directory