Improve tool action hierarchy - #278

Summary

• separate the global favorite control from tool-specific actions with a dedicated grouped region and visual divider
• move Log Scrubber onto the shared ToolActionBar with Sample, Clear, Scrub, Copy, and Send to actions
• add regression coverage for HTTP Request Builder header entry not toggling favorites and extend action consistency guards for the audited tools

Validation

• npm test -- tests/component/http-request-builder-page.test.tsx tests/guards/phase1-developer-utilities-pages.test.tsx tests/guards/tool-action-consistency-guard.test.ts
• npm run check:types
• npm run check:i18n
• npm run lint
• npm run build:app

Closes #245