refactor(styles): simplify admin color token vocabulary

[DavidBabinec]

What changed

• Replaced the overlapping admin/editor color token vocabulary with direct Core Framework-style globals: --bg-*, --text-*, --border*, --overlay-*, --scrim-*, --accent-*, and semantic state tokens.
• Migrated admin/ui/module styles and token helper utilities to consume the new globals directly instead of mapping through --editor-*, --panel-*, rail tint, or tag pill tint color aliases.
• Added an architecture gate to prevent deprecated token families from coming back, and updated docs/tests to describe the new token model.

Why

The previous token set had several overlapping alias layers, especially editor/panel-prefixed color variables. This keeps the admin chrome closer to the Core Framework vocabulary and makes token usage easier to audit.

Impact

Pure styling-token refactor. No runtime behavior changes intended beyond using the renamed token source of truth.

Verification

• bun run build
• bun test
• bun run lint
• bun test src/__tests__/architecture/css-token-vocabulary.test.ts src/__tests__/architecture/css-token-policy.test.ts src/__tests__/architecture/no-css-var-fallbacks.test.ts src/__tests__/architecture/scrollbar-chrome.test.ts src/__tests__/canvas/editorChromeInjector.test.tsx

Note

react-doctor --diff origin/main --fail-on warning --no-score reports existing warning-tier component diagnostics in TSX files touched only for token-string/comment updates. I left those unrelated component refactors out of this PR.